Gain of Metabolic Benefit with Ablation of miR-149-3p from Subcutaneous Adipose Tissue in Diet-Induced Obese Mice

Directly targeting PRDM16 in thermogenic adipose tissue to treat obesity and its related metabolic diseases

Obesity is increasing globally and is closely associated with a range of metabolic disorders, including metabolic associated fatty liver disease, diabetes, and cardiovascular diseases. An effective strategy to combat obesity involves stimulating brown and beige adipocyte thermogenesis, which significantly enhances energy expenditure. Recent research has underscored the vital role of PRDM16 in the development and functionality of thermogenic adipocytes. Consequently, PRDM16 has been identified as a potential therapeutic target for obesity and its related metabolic disorders. This review comprehensively examines various studies that focus on combating obesity by directly targeting PRDM16 in adipose tissue.

Hepatic miR-149-5p upregulation fosters steatosis, inflammation and fibrosis development in mice and in human liver organoids

Background & Aims

The incidence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing worldwide. Alterations of hepatic microRNA (miRNA) expression/activity significantly contribute to the development and progression of MASLD. Genetic polymorphisms of miR-149 are associated with an increased susceptibility to MASLD development in humans. Aberrant expression of miR-149 was also associated with metabolic alterations in several organs, but the impact of hepatic miR-149-5p deregulation in MASLD remains poorly characterized.

Methods

MiR-149-5p was downregulated in the livers of mice by in vivo transduction with hepatotropic adeno-associated virus 8 harboring short-hairpin RNAs (shRNAs) specific for miR-149-5p (shmiR149) or scrambled shRNAs (shCTL). MASLD was then induced with a methionine/choline-deficient (MCD, n = 7 per group) diet or a fructose/palmitate/cholesterol-enriched (FPC, n = 8-12 per group, per protocol) diet. The impact of miR-149-5p modulation on MASLD development was assessed in vivo and in vitro using multi-lineage 3D human liver organoids (HLOs) and Huh7 cells.

Results

MiR-149-5p expression was strongly upregulated in mouse livers from different models of MASLD (2-4-fold increase in ob/ob, db/db mice, high-fat and FPC-fed mice). In vivo downregulation of miR-149-5p led to an amelioration of diet-induced hepatic steatosis, inflammation/fibrosis, and to increased whole-body fatty acid consumption. In HLOs, miR-149-5p overexpression promoted lipid accumulation, inflammation and fibrosis. In vitro analyses of human Huh7 cells overexpressing miR-149-5p indicated that glycolysis and intracellular lipid accumulation was promoted, while mitochondrial respiration was impaired. Translatomic analyses highlighted deregulation of multiple potential miR-149-5p targets in hepatocytes involved in MASLD development.

Conclusions

MiR-149-5p upregulation contributes to MASLD development by affecting multiple metabolic/inflammatory/fibrotic pathways in hepatocytes. Our results further demonstrate that HLOs are a relevant 3D in vitro model to investigate hepatic steatosis and inflammation/fibrosis development.

Impact and implications

Our research shows compelling evidence that miR-149-5p plays a pivotal role in the development and progression of MASLD. By employing in vivo and innovative in vitro models using multi-lineage human liver organoids, we demonstrate that miR-149-5p upregulation significantly impacts hepatocyte energy metabolism, exacerbating hepatic steatosis and inflammation/fibrosis by modulating a wide network of target genes. These findings not only shed light on the intricate miR-149-5p-dependent molecular mechanisms underlying MASLD, but also underscore the importance of human liver organoids as valuable 3D in vitro models for studying the disease's pathogenesis.

Integrative bioinformatics analysis to screen key genes and signalling pathways related to ferroptosis in obesity

Ferroptosis is closely associated with the development of disease in the body. However, there are few studies on ferroptosis-related genes (FRGs) in obesity. Therefore, key genes and signalling pathways related to ferroptosis in obesity were screened. Briefly, the RNA sequencing data of obesity and the non-obesity human samples and 259 FRGs were downloaded from GEO database and FerrDb database, respectively. The obesity-related module genes were firstly screened by weighted gene co-expression network analysis (WGCNA) and crossed with differentially expressed genes (DEGs) of obesity/normal samples and FRGs to obtain obesity-ferroptosis related (OFR) DEGs. Then, key genes were screened by PPI network. Next, the correlation of key genes and differential immune cells between obesity and normal samples were further explored by immune infiltration analysis. Finally, microRNA (miRNA)-messenger RNA (mRNA), transcription factor (TF)-mRNA networks and drug-gene interaction networks were constructed. As a result, 17 OFR DEGs were obtained, which mainly participated in processes such as lipid metabolism or adipocyte differentiation. The 4 key genes, STAT3, IL-6, PTGS2, and VEGFA, constituted the network. M2 macrophages, T cells CD8, mast cells activated, and T cells CD4 memory resting had significant differences between obesity and normal samples. Moreover, 51 miRNAs and 164 drugs were predicted for 4 key genes. All in all, this study has screened 4 FRGs, including IL-6, VEGFA, STAT3, and PTGS2, in obesity patients.

Effect of miR-149-5p on intramuscular fat deposition in pigs based on metabolomics and transcriptomics

As one of the important traits in pig production, meat quality has important research significance and value. Intramuscular fat (IMF) content is one of the most important factors affecting pork quality. Many experimental studies have shown that IMF content is closely related to the flavor, tenderness, and juiciness of pork. Therefore, it is of great significance to study the mechanism of porcine IMF deposition. Previous research indicated that miR-149-5p promoted the proliferation of porcine intramuscular (IM) preadipocytes and decreased their ability to differentiate, albeit the exact mechanism of action is unknown. In vitro, foreign pigs showed increased miR-149-5p expression and reduced fat deposition when compared to Queshan Black pigs. This study conducted metabolomics and transcriptomics analyses of porcine IM preadipocytes overexpressing miR-149-5p to verify their effects on lipid formation. According to metabolomics analysis, the overexpression of miR-149-5p has significantly altered the lipid, organic acid, and organic oxygen metabolites of porcine IM preadipocytes. Specially speaking, it has changed 115 metabolites, including 105 up-regulated and 10 down-regulated ones, as well as the composition of lipid, organic acid, and organic oxygen metabolism-related metabolites. RNA-seq analysis showed that overexpression of miR-149-5p significantly altered 857 genes, of which 442 were up-regulated, and 415 were down-regulated, with enrichment to MAPK, IL-17, PI3K-Akt, and ErbB signaling pathways. We found that overexpression of miR-149-5p inhibited adipogenic differentiation by changing cAMP signaling pathway in porcine IM preadipocytes. In addition, the overexpression of miR-149-5p may affect the transport of Cu²⁺ by targeting ATP7A and inhibiting adipogenic differentiation. These findings elucidate the regulatory function of miR-149-5p in porcine IM preadipocytes, which may be a key target for controlling pork quality.

Potential Mechanisms of Gut-Derived Extracellular Vesicle Participation in Glucose and Lipid Homeostasis

The intestine participates in the regulation of glucose and lipid metabolism in multiple facets. It is the major site of nutrient digestion and absorption, provides the interface as well as docking locus for gut microbiota, and harbors hormone-producing cells scattered throughout the gut epithelium. Intestinal extracellular vesicles are known to influence the local immune response, whereas their roles in glucose and lipid homeostasis have barely been explored. Hence, this current review summarizes the latest knowledge of cargo substances detected in intestinal extracellular vesicles, and connects these molecules with the fine-tuning regulation of glucose and lipid metabolism in liver, muscle, pancreas, and adipose tissue.

CircSETBP1 Acts as a MiR-149-5p Sponge to Promote Intramuscular Fat Deposition by Regulating CRTCs

Circular RNAs (circRNAs) appear to be crucial in the process of adipogenesis according to mounting data. CircSETBP1 is a newly discovered circRNA associated with adipogenesis. Sequencing verification and RNase R treatment have confirmed the circular nature of circSETBP1 in porcine tissue. The precise function and mechanism of circSETBP1 in adipocyte biology are still unclear. Cell counting kit-8 (CCK8), Oil red O staining, and quantitative real-time polymerase chain reaction (qRT-PCR) were employed in this investigation to reveal the functions of circSETBP1 and miR-149-5p in the growth and development of porcine intramuscular (IM) preadipocytes. CircSETBP1 overexpression accelerated cell differentiation while reducing cell proliferation. The opposite outcome was produced by overexpressing miR-149-5p. Meanwhile, circSETBP1 down-regulated the expression of miR-149-5p and miR-149-5p restrained the expression of CRTC1/CRTC2. CircSETBP1 was directly targeted by miR-149-5p, and CRTC1/CRTC2 were the target genes of miR-149-5p using bioinformatic analysis, the dual-Luciferase reporter system, and qRT-PCR. In conclusion, circSETBP1 controls the proliferation and differentiation of porcine IM preadipocytes and 3T3-L1 cells by regulating the miR-149-5p/CRTCs axis. The results of this study not only illuminate the molecular mechanism of circSETBP1/miR-149-5p involved in the deposition of porcine intramuscular fat (IMF), but they also provide a significant theoretical reference for raising quality of pork.

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.

Joint detection of miR-149-3p and hepcidin predicts the onset of obstructive sleep apnea syndrome in obese patients

Background

Obstructive sleep apnea syndrome (OSAS) is a potentially fatal sleep respiratory disorder, and hepcidin has been found to be related with OSAS onset and severity. This study aimed to examine the serum expression of microRNA-149-3p (miR-149-3p) and hepcidin in OSAS patients, and evaluate the predictive value of miR-149-3p and hepcidin for OSAS occurrence in obese population.

Methods

This study analyzed the data from 212 OSAS patients and 120 control individuals. OSAS severity was evaluated by apnea hypopnea index (AHI) from polysomnography. Serum miR-149-3p was examined using reverse transcription quantitative PCR, and hepcidin and inflammatory cytokines were measured using ELISA kits. Logistic regression analysis was used to evaluate the predictive value of miR-142-3p and hepcidin for OSAS in obese population, and ROC curve was plotted to assess the predictive accuracy.

Results

Serum miR-149-3p and hepcidin were increased in OSAS patients, especially in the severe cases, and had diagnostic potential to distinguish OSAS. High miR-149-3p and hepcidin were positively correlated with OSAS patients' inflammatory cytokines. Obese OSAS patients had the highest miR-149-3p and hepcidin levels, and the two molecules had predictive value of OSAS present in obese population, and the combination of miR-149-3p and hepcidin showed the highest predictive accuracy.

Conclusion

Serum miR-149-3p and hepcidin levels were elevated in OSAS patients and correlated with disease severity and systemic inflammation. miR-149-3p and hepcidin levels have diagnostic value to distinguish OSAS, exhibited predictive value for OSAS in obese population, and the joint detection of the two molecules showed the highest predictive accuracy.

PRDM16 Regulating Adipocyte Transformation and Thermogenesis: A Promising Therapeutic Target for Obesity and Diabetes

Given that obesity and diabetes have been major public health concerns and that disease morbidities have been rising continuously, effective treatment for these diseases is urgently needed. Because adipose tissue metabolism is involved in the progression of obesity and diabetes, it might be efficient to target adipocyte metabolic pathways. Positive regulatory domain zinc finger region protein 16 (PRDM16), a transcription factor that is highly expressed in adipocytes, plays a key role in adipose tissue metabolism, such as the browning and thermogenesis of adipocytes, the beigeing of adipocytes, the adipogenic differentiation of myoblasts, and the conversion of visceral adipocytes to subcutaneous adipocytes. Furthermore, clinical and basic studies have shown that the expression of PRDM16 is associated with obesity and diabetes and that PRDM16 signaling participates in the treatment of the two diseases. For example, metformin promotes thermogenesis and alleviates obesity by activating the AMPK/αKG/PRDM16 signaling pathway; rosiglitazone alleviates obesity under the synergistic effect of PRDM16; resveratrol plays an antiobesity role by inducing the expression of PRDM16; liraglupeptide improves insulin resistance by inducing the expression of PRDM16; and mulberry leaves play an anti-inflammatory and antidiabetes role by activating the expression of brown fat cell marker genes (including PRDM16). In this review, we summarize the evidence of PRDM16 involvement in the progression of obesity and diabetes and that PRDM16 may be a promising therapy for obesity and diabetes.

Biochemical and immunological changes in obesity

Obesity is a syndemia that promotes high expenditures for public health, and is defined by the excess of adipose tissue that is classified according to its function and anatomical distribution. In obese people, this tissue generates oxidative stress associated with a chronic inflammatory response, in which there is an imbalance in relation to the release of hormones and adipokines that cause loss of body homeostasis and predisposition to the development of some comorbidities. The purpose of this review is to summarize the main events that occur during the onset and progression of obesity with a special focus on biochemical and immunological changes. Hypertrophied and hyperplasia adipocytes have biomarkers and release adipokines capable of regulating pathways and expressing genes that culminate in the development of metabolic changes, such as changes in energy balance and intestinal microbiota, and the development of some comorbidities, diabetes mellitus, dyslipidemias, arterial hypertension, liver disease, cancer, allergies, osteoporosis, sarcopenia and obstructive sleep apnea. Thus, it is necessary to treat and/or prevent pathology, using traditional methods based on healthy eating, and regular physical and leisure activities.

Analysis of lncRNA-miRNA-mRNA expression pattern in heart tissue after total body radiation in a mouse model

Background

Radiation therapy is integral to effective thoracic cancer treatments, but its application is limited by sensitivity of critical organs such as the heart. The impacts of acute radiation-induced damage and its chronic effects on normal heart cells are highly relevant in radiotherapy with increasing lifespans of patients. Biomarkers for normal tissue damage after radiation exposure, whether accidental or therapeutic, are being studied as indicators of both acute and delayed effects. Recent research has highlighted the potential importance of RNAs, including messenger RNAs (mRNAs), microRNAs (miRNAs), and long non-coding RNAs (lncRNAs) as biomarkers to assess radiation damage. Understanding changes in mRNA and non-coding RNA expression will elucidate biological pathway changes after radiation.

Methods

To identify significant expression changes in mRNAs, lncRNAs, and miRNAs, we performed whole transcriptome microarray analysis of mouse heart tissue at 48 h after whole-body irradiation with 1, 2, 4, 8, and 12 Gray (Gy). We also validated changes in specific lncRNAs through RT-qPCR. Ingenuity Pathway Analysis (IPA) was used to identify pathways associated with gene expression changes.

Results

We observed sustained increases in lncRNAs and mRNAs, across all doses of radiation. Alas2, Aplnr, and Cxc3r1 were the most significantly downregulated mRNAs across all doses. Among the significantly upregulated mRNAs were cell-cycle arrest biomarkers Gdf15, Cdkn1a, and Ckap2. Additionally, IPA identified significant changes in gene expression relevant to senescence, apoptosis, hemoglobin synthesis, inflammation, and metabolism. LncRNAs Abhd11os, Pvt1, Trp53cor1, and Dino showed increased expression with increasing doses of radiation. We did not observe any miRNAs with sustained up- or downregulation across all doses, but miR-149-3p, miR-6538, miR-8101, miR-7118-5p, miR-211-3p, and miR-3960 were significantly upregulated after 12 Gy.

Conclusions

Radiation-induced RNA expression changes may be predictive of normal tissue toxicities and may indicate targetable pathways for radiation countermeasure development and improved radiotherapy treatment plans.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02998-w.

Pancreatic β cells control glucose homeostasis via the secretion of exosomal miR-29 family

Secreted microRNAs (miRNAs) are novel endocrine factors that play essential pathological and physiological roles. Here, we report that pancreatic β cell-released exosomal miR-29 family members (miR-29s) regulate hepatic insulin sensitivity and control glucose homeostasis. Cultured pancreatic islets were shown to secrete miR-29s in response to high levels of free fatty acids (FFAs) in vitro. In vivo, high levels of FFAs, promoted by either high-fat diet (HFD) feeding (physiopathological) or fasting (physiological), increased the secretion of miR-29s into plasma. Intravenous administration of exosomal miR-29s attenuated insulin sensitivity. The overexpression of miR-29s in the β cells of transgenic (TG) mice promoted the secretion of miR-29s and inhibited the insulin-mediated suppression of glucose output in the liver. We used selective overexpression of traceable heterogenous mutant miR-29s in β cells to confirm that islet-derived exosomal miR-29s target insulin signalling in the liver and blunt hepatic insulin sensitivity. Moreover, in vivo disruption of miR-29s expression in β cells reversed HFD-induced insulin resistance. In vitro experiments demonstrated that isolated exosomes enriched in miR-29s inhibited insulin signalling in the liver and increased hepatic glucose production. These results unveil a novel β cell-derived secretory signal-exosomal miR-29s-and provide insight into the roles of miR-29s in manipulating glucose homeostasis.