miRNA Dysregulation in the Development of Non-Alcoholic Fatty Liver Disease and the Related Disorders Type 2 Diabetes Mellitus and Cardiovascular Disease

Impact of Combined Aerobic Training and Magnesium Supplementation on Serum Biomarkers and microRNA-155 and microRNA-21 Expression in Adipose Tissue of Type 2 Diabetic Rats: An Eight-Week Interventional Study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder characterized by insulin resistance and chronic inflammation. Aerobic training (AT) and magnesium supplementation (Mg) have both been independently shown to have beneficial effects on glucose control and insulin sensitivity in individuals with T2DM. However, the potential synergistic effects of combining AT and Mg supplementation have not been extensively studied. This study aimed to investigate the effects of an 8-week AT and Mg supplementation on serum levels of insulin, glucose, leptin, adiponectin, TNF-α, IL-1β, IL-6, NF-κB, as well as the expression of mir-155 and mir-21 in the visceral adipose tissue (VAT) of rats with T2DM.

METHODS

For this experimental study, 32 male Wistar rats were induced with T2DM by a high-fat diet combined with a low-dose streptozotocin injection. The rats were randomly assigned to four groups: AT and Mg supplementation (AT + Mg), AT (5 days/week for 8 weeks), Mg supplementation (received daily supplementation of Mg chloride), and diabetic control (C). An 8-week AT program was implemented, with gradually increasing the intensity and duration to reach 25 m/min and 60 min in the 8th week, respectively. The training intensity was set at 50-60% of VO2max. The Mg groups were provided with rat diets containing 1000 mg/kg of Mg. The AT + Mg group received both interventions, while the C group served as the untreated control. Serum biomarkers were measured using enzyme-linked immunosorbent assay (ELISA), and VAT samples were collected for gene expression analysis using real-time polymerase chain reaction (PCR).

RESULTS

Serum biomarker analysis revealed that the AT + Mg group had a significant decrease in fasting insulin (p = 0.001) and serum glucose (p = 0.001), as well as an increase in adiponectin levels compared to the C group (p = 0.002). Additionally, the AT + Mg group showed a significant reduction in serum leptin, TNF-α, IL-6, IL-1β, and NF-κB, as well as downregulation of mir-155 and mir-21 in the VAT compared to the other groups. The AT group also showed improvements in several parameters, while the Mg group had fewer significant differences compared to the C group.

CONCLUSION

The combination of AT and Mg supplementation provides a synergistic effect that improves serum biomarkers and downregulates pro-inflammatory microRNAs in the VAT of T2DM rats. Meanwhile, Mg supplementation alone does not have a significant effect on pro-inflammatory microRNAs in the VAT. These findings suggest that such combined interventions could be a promising strategy for managing T2DM, potentially ameliorating inflammatory states and improving metabolic health.

Role of microRNA in non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH): a comprehensive review

Non-alcoholic fatty liver disease (NAFLD) is a prevalent liver condition that affects people who do not overconsume alcohol. Uncertainties exist over how microRNAs (miRNAs) in the blood and liver relate to NAFLD. The aim of this narrative review was to investigate the role of miRNAs in the onset and progression of non-alcoholic steatohepatitis (NASH) from NAFLD, and explore their potential as diagnostic tools and treatment targets for NAFLD patients. Liver miRNA-34a levels were found to accurately represent the degree of liver damage, with lower levels suggesting more damage. In patients with NAFLD and severe liver fibrosis, higher levels of miRNA-193a-5p and miRNA-378d were found. Moreover, miRNA-34a, miRNA-122, and miRNA-192 levels might aid in differentiating NASH from NAFLD. Similar to this, miRNA-21 and miRNA-27 levels in rats were able to distinguish between steatosis and steatohepatitis. High-fat diets enhanced the expression of 15 distinct miRNAs in rats, and there were substantial differences in the miRNA expression patterns between obese and lean people. The results from the present review imply that miRNA microarrays and sequencing may be helpful diagnostic tools, and miRNAs may be a possible treatment target for patients with NAFLD.

Evaluation of miRNA-7, miRNA-10 and miRNA-21 as diagnostic non-invasive biomarkers of hepatocellular carcinoma

Aim of the study

Liver cancer (hepatocellular carcinoma - HCC) remains a serious health challenge; it is the fourth leading cause of death worldwide. Egypt ranks fifteenth worldwide and the third in Africa in terms of HCC burden. The present study aimed to assess some microRNAs (miRNAs) including miRNA-7, miRNA-10, and miRNA-21, serum markers such as cluster of differentiation-14 (CD-14) and transforming growth factor b1 (TGF-b1), and other biochemical parameters as non-invasive tools for HCC diagnosis.

Material and methods

The study included 100 participants divided into five groups: group I (20 normal subjects as a healthy group), group II (20 participants with chronic HCV infection but non-cirrhotic), group III (20 volunteers with chronic HCV infection and compensated cirrhosis), group IV (20 patients with chronic HCV infection and decompensated cirrhosis), and group V (20 participants with HCC). Levels of miR-7, miR-10, and miR-21 were evaluated using qRT-PCR. Serum ALT, AST, total bilirubin, total protein, albumin, PT, INR, and platelet count were determined. FIB-4 and APRI test levels were also calculated. CD-14 and TGF-β1 serum levels were estimated using enzyme-linked immunosorbent assay (ELISA) kits.

Results

The expression levels of miR-21 followed by miR-10 showed high sensitivity and specificity in predicting HCC. Serum CD-14 and TGF-b1 levels were significantly increased in all patient groups.

Conclusions

From the study, it is concluded that the expression level of miR-21 has the highest sensitivity and specificity, followed by miR-10, which has high sensitivity and low specificity as non-invasive markers for HCC detection, while miR-7 exhibits high sensitivity and reasonable specificity in fibrosis detection.

Role of miR-15a-5p and miR-199a-3p in the inflammatory pathway regulated by NF-κB in experimental and human atherosclerosis

BACKGROUND

Cardiovascular diseases (CVDs) prevalence has significantly increased in the last decade and atherosclerosis development is the main trigger. MicroRNAs (miRNAs) are non-coding RNAs that negatively regulate gene expression of their target and their levels are frequently altered in CVDs.

METHODS

By RT-qPCR, we analysed miR-9-5p, miR-15a-5p, miR-16-5p and miR-199a-3p levels in aorta from apolipoprotein knockout (ApoE-/- ) mice, an experimental model of hyperlipidemia-induced atherosclerosis, and in human aortic and carotid atherosclerotic samples. By in silico studies, Western blot analysis and immunofluorescence studies, we detected the targets of the altered miRNAs.

RESULTS

Our results show that miR-15a-5p and miR-199a-3p are significantly decreased in carotid and aortic samples from patients and mice with atherosclerosis. In addition, we found an increased expression in targets of both miRNAs that participate in the inflammatory pathway of nuclear factor kappa B (NF-κB), such as IKKα, IKKβ and p65. In human vein endothelial cells (HUVECs) and vascular smooth muscle cells (VSMCs), the overexpression of miR-15a-5p or miR-199a-3p decreased IKKα, IKKβ and p65 protein levels as well as NF-κB activation. On the other hand, miR-15a-5p and miR-199a-3p overexpression reduced ox-LDL uptake and the inflammation regulated by NF-κB in VSMCs. Moreover, although miR-15a-5p and miR-199a-3p were significantly increased in exosomes from patients with advanced carotid atherosclerosis, only in the ROC analyses for miR-15a-5p, the area under the curve was 0.8951 with a p value of .0028.

CONCLUSIONS

Our results suggest that the decrease of miR-199a-3p and miR-15a-5p in vascular samples from human and experimental atherosclerosis could be involved in the NF-κB activation pathway, as well as in ox-LDL uptake by VSMCs, contributing to inflammation and progression atherosclerosis. Finally, miR-15a-5p could be used as a novel diagnostic biomarker for advanced atherosclerosis.

Targeted MicroRNA Profiling Reveals That Exendin-4 Modulates the Expression of Several MicroRNAs to Reduce Steatosis in HepG2 Cells

Excess hepatic lipid accumulation is the hallmark of non-alcoholic fatty liver disease (NAFLD), for which no medication is currently approved. However, glucagon-like peptide-1 receptor agonists (GLP-1RAs), already approved for treating type 2 diabetes, have lately emerged as possible treatments. Herein we aim to investigate how the GLP-1RA exendin-4 (Ex-4) affects the microRNA (miRNAs) expression profile using an in vitro model of steatosis. Total RNA, including miRNAs, was isolated from control, steatotic, and Ex-4-treated steatotic cells and used for probing a panel of 799 highly curated miRNAs using NanoString technology. Enrichment pathway analysis was used to find the signaling pathways and cellular functions associated with the differentially expressed miRNAs. Our data shows that Ex-4 reversed the expression of a set of miRNAs. Functional enrichment analysis highlighted many relevant signaling pathways and cellular functions enriched in the differentially expressed miRNAs, including hepatic fibrosis, insulin receptor, PPAR, Wnt/β-Catenin, VEGF, and mTOR receptor signaling pathways, fibrosis of the liver, cirrhosis of the liver, proliferation of hepatic stellate cells, diabetes mellitus, glucose metabolism disorder and proliferation of liver cells. Our findings suggest that miRNAs may play essential roles in the processes driving steatosis reduction in response to GLP-1R agonists, which warrants further functional investigation.

Insight into the Inter-Organ Crosstalk and Prognostic Role of Liver-Derived MicroRNAs in Metabolic Disease Progression

Dysfunctional hepatic metabolism has been linked to numerous diseases, including non-alcoholic fatty liver disease, the most common chronic liver disorder worldwide, which can progress to hepatic fibrosis, and is closely associated with insulin resistance and cardiovascular diseases. In addition, the liver secretes a wide array of metabolites, biomolecules, and microRNAs (miRNAs) and many of these secreted factors exert significant effects on metabolic processes both in the liver and in peripheral tissues. In this review, we summarize the involvement of liver-derived miRNAs in biological processes with an emphasis on delineating the communication between the liver and other tissues associated with metabolic disease progression. Furthermore, the review identifies the primary molecular targets by which miRNAs act. These consolidated findings from numerous studies provide insight into the underlying mechanism of various metabolic disease progression and suggest the possibility of using circulatory miRNAs as prognostic predictors and therapeutic targets for improving clinical intervention strategies.

Cardiac Metabolism and MiRNA Interference

The aberrant increase in cardio-metabolic diseases over the past couple of decades has drawn researchers' attention to explore and unveil the novel mechanisms implicated in cardiometabolic diseases. Recent evidence disclosed that the derangement of cardiac energy substrate metabolism plays a predominant role in the development and progression of chronic cardiometabolic diseases. Hence, in-depth comprehension of the novel molecular mechanisms behind impaired cardiac metabolism-mediated diseases is crucial to expand treatment strategies. The complex and dynamic pathways of cardiac metabolism are systematically controlled by the novel executor, microRNAs (miRNAs). miRNAs regulate target gene expression by either mRNA degradation or translational repression through base pairing between miRNA and the target transcript, precisely at the 3' seed sequence and conserved heptametrical sequence in the 5' end, respectively. Multiple miRNAs are involved throughout every cardiac energy substrate metabolism and play a differential role based on the variety of target transcripts. Novel theoretical strategies have even entered the clinical phase for treating cardiometabolic diseases, but experimental evidence remains inadequate. In this review, we identify the potent miRNAs, their direct target transcripts, and discuss the remodeling of cardiac metabolism to cast light on further clinical studies and further the expansion of novel therapeutic strategies. This review is categorized into four sections which encompass (i) a review of the fundamental mechanism of cardiac metabolism, (ii) a divulgence of the regulatory role of specific miRNAs on cardiac metabolic pathways, (iii) an understanding of the association between miRNA and impaired cardiac metabolism, and (iv) summary of available miRNA targeting therapeutic approaches.

Exploring the Regulatory Role of ncRNA in NAFLD: A Particular Focus on PPARs

Liver diseases are responsible for global mortality and morbidity and are a significant cause of death worldwide. Consequently, the advancement of new liver disease targets is of great interest. Non-coding RNA (ncRNA), such as microRNA (miRNA) and long ncRNA (lncRNA), has been proven to play a significant role in the pathogenesis of virtually all acute and chronic liver disorders. Recent studies demonstrated the medical applications of miRNA in various phases of hepatic pathology. PPARs play a major role in regulating many signaling pathways involved in various metabolic disorders. Non-alcoholic fatty liver disease (NAFLD) is the most prevalent form of chronic liver disease in the world, encompassing a spectrum spanning from mild steatosis to severe non-alcoholic steatohepatitis (NASH). PPARs were found to be one of the major regulators in the progression of NAFLD. There is no recognized treatment for NAFLD, even though numerous clinical trials are now underway. NAFLD is a major risk factor for developing hepatocellular carcinoma (HCC), and its frequency increases as obesity and diabetes become more prevalent. Reprogramming anti-diabetic and anti-obesity drugs is an effective therapy option for NAFLD and NASH. Several studies have also focused on the role of ncRNAs in the pathophysiology of NAFLD. The regulatory effects of these ncRNAs make them a primary target for treatments and as early biomarkers. In this study, the main focus will be to understand the regulation of PPARs through ncRNAs and their role in NAFLD.

Liver-derived metabolites as signaling molecules in fatty liver disease

Excessive fat accumulation in the liver has become a major health threat worldwide. Unresolved fat deposition in the liver can go undetected until it develops into fatty liver disease, followed by steatohepatitis, fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Lipid deposition in the liver is governed by complex communication, primarily between metabolic organs. This can be mediated by hormones, organokines, and also, as has been more recently discovered, metabolites. Although how metabolites from peripheral organs affect the liver is well documented, the effect of metabolic players released from the liver during the development of fatty liver disease or associated comorbidities needs further attention. Here we focus on interorgan crosstalk based on metabolites released from the liver and how these molecules act as signaling molecules in peripheral tissues. Due to the liver's specific role, we are covering lipid and bile mechanism-derived metabolites. We also discuss the high sucrose intake associated with uric acid release from the liver. Excessive fat deposition in the liver during fatty liver disease development reflects disrupted metabolic processes. As a response, the liver secretes a variety of signaling molecules as well as metabolites which act as a footprint of the metabolic disruption. In the coming years, the reciprocal exchange of metabolites between the liver and other metabolic organs will gain further importance and will help to better understand the development of fatty liver disease and associated diseases.

MiR-103-3p promotes hepatic steatosis to aggravate nonalcoholic fatty liver disease by targeting of ACOX1

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a major risk factor for hepatocellular carcinoma, and alterations in miRNA expression are related to the development of NAFLD. However, the role of miRNAs in regulating the development of NAFLD is still poorly understood.

METHODS

We used qRT-PCR to detect the level of miR-103-3p in both cell and mouse models of NAFLD. Biochemical assays, DCF-DA assays, Oil red O staining and HE staining were used to detect the role of miR-103-3p in NAFLD development. Target genes of miR-103-3p were predicted using the TargetScan database and verified by qRT-PCR, western blot and dual-luciferase assays.

RESULTS

The expression of miR-103-3p increased in both NAFLD model cells and liver tissues from the NAFLD mouse model. Inhibition of miR-103-3p significantly alleviated the accumulation of lipid droplets in free fatty acid-treated L02 cells and liver tissues from mice with NAFLD. Inhibition of miR-103-3p reduced the contents of H2O2, TG, ALT, and AST and ROS production while increasing the ATP content. Moreover, the miR-103-3p antagomir alleviated liver tissue lesions in mice with NAFLD. Further studies identified ACOX1, a key enzyme for the oxidation and decomposition of fatty acids, as a direct target of miR-103-3p.

CONCLUSIONS

These findings identified a negative regulatory mechanism between ACOX1 and miR-103-3p that promotes the pathogenesis of NAFLD and suggested that inhibition of miR-103-3p may be a potential treatment strategy for NAFLD.

Circulating MicroRNAs as a Tool for Diagnosis of Liver Disease Progression in People Living with HIV-1

MicroRNAs (miRNAs) are small, non-coding RNAs that post-transcriptionally regulate gene expression by binding specific cell mRNA targets, preventing their translation. miRNAs are implicated in the regulation of important physiological and pathological pathways. Liver disease, including injury, fibrosis, metabolism dysregulation, and tumor development disrupts liver-associated miRNAs. In addition to their effect in the originating tissue, miRNAs can also circulate in body fluids. miRNA release is an important form of intercellular communication that plays a role in the physiological and pathological processes underlying multiple diseases. Circulating plasma levels of miRNAs have been identified as potential disease biomarkers. One of the main challenges clinics face is the lack of available noninvasive biomarkers for diagnosing and predicting the different stages of liver disease (e.g., nonalcoholic fatty liver disease and nonalcoholic steatohepatitis), particularly among individuals infected with human immunodeficiency virus type 1 (HIV-1). Liver disease is a leading cause of death unrelated to acquired immunodeficiency syndrome (AIDS) among people living with HIV-1 (PLWH). Here, we review and discuss the utility of circulating miRNAs as biomarkers for early diagnosis, prognosis, and assessment of liver disease in PLWH. Remarkably, the identification of dysregulated miRNA expression may also identify targets for new therapeutics.

An Update in Epigenetics in Metabolic-Associated Fatty Liver Disease

Metabolic-associated fatty liver disease (MAFLD) is characterized by hepatic steatosis accompanied by one of three features: overweight or obesity, T2DM, or lean or normal weight with evidence of metabolic dysregulation. It is distinguished by excessive fat accumulation in hepatocytes, and a decrease in the liver's ability to oxidize fats, the accumulation of ectopic fat, and the activation of proinflammatory pathways. Chronic damage will keep this pathophysiologic cycle active causing progression from hepatic steatosis to cirrhosis and eventually, hepatocarcinoma. Epigenetics affecting gene expression without altering DNA sequence allows us to study MAFLD pathophysiology from a different perspective, in which DNA methylation processes, histone modifications, and miRNAs expression have been closely associated with MAFLD progression. However, these considerations also faced us with the circumstance that modifying those epigenetics patterns might lead to MAFLD regression. Currently, epigenetics is an area of great interest because it could provide new insights in therapeutic targets and non-invasive biomarkers. This review comprises an update on the role of epigenetic patterns, as well as innovative therapeutic targets and biomarkers in MAFLD.

A Structural View of miRNA Biogenesis and Function

Micro-RNAs (miRNAs) are a class of non-coding RNAs (ncRNAs) that act as post-transcriptional regulators of gene expression. Since their discovery in 1993, they have been the subject of deep study due to their involvement in many important biological processes. Compared with other ncRNAs, miRNAs are generated from devoted transcriptional units which are processed by a specific set of endonucleases. The contribution of structural biology methods for understanding miRNA biogenesis and function has been essential for the dissection of their roles in cell biology and human disease. In this review, we summarize the application of structural biology for the characterization of the molecular players involved in miRNA biogenesis (processors and effectors), starting from the X-ray crystallography methods to the more recent cryo-electron microscopy protocols.

Gallic Acid Improves Diabetic Steatosis by Downregulating MicroRNA-34a-5p through Targeting NFE2L2 Expression in High-Fat Diet-Fed db/db Mice

Type 2 diabetes mellitus (T2DM) has become epidemic worldwide and is strongly associated with nonalcoholic fatty liver disease (NAFLD). The molecular mechanisms of microRNAs in NAFLD and T2DM development and the corresponding therapies remain unclear. We performed microRNA microarray validation to determine whether hepatic miR-34a-5p was significantly upregulated in db/db mice fed with a high-fat diet (HFD), a mouse model of T2DM with steatohepatitis. The potential role of miR-34a-5p and gallic acid (GA) in regulating hepatic lipid metabolism and diabetic steatosis was explored. GA improved the activities of antioxidant enzymes and suppressed lipid accumulation in the HFD-induced steatotic liver of db/db mice. In vitro, the silencing of miR-34a-5p in hepatocyte HepG2 cells ameliorated high glucose + oleic acid/palmitic acid mixture–induced accumulation of cellular triglycerides. We identified nuclear factor erythroid-derived 2-like 2 (NFE2L2) as a direct target of miR-34a-5p. Reduction in intracellular triglyceride and the expression levels of sterol regulatory element-binding protein 1 and fatty acid synthase by GA were mediated by the inhibition of miR-34a-5p expression in HepG2 cells. The findings suggest that GA improves hepatic lipogenesis by downregulating miR-34a-5p by suppressing NFE2L2 expression, indicating the potential therapeutic role of GA or an NFE2L2-activating agent in diabetic fatty liver disease.

Severe Hepatic Insulin Resistance Induces Vascular Dysfunction: Improvement by Liver-Specific Insulin Receptor Isoform A Gene Therapy in a Murine Diabetic Model

BACKGROUND

Cardiovascular dysfunction is linked to insulin-resistant states. In this paper, we analyzed whether the severe hepatic insulin resistance of an inducible liver-specific insulin receptor knockout (iLIRKO) might generate vascular insulin resistance and dysfunction, and whether insulin receptor (IR) isoforms gene therapy might revert it.

METHODS

We studied in vivo insulin signaling in aorta artery and heart from iLIRKO. Vascular reactivity and the mRNA levels of genes involved in vascular dysfunction were analyzed in thoracic aorta rings by qRT-PCR. Finally, iLIRKO mice were treated with hepatic-specific gene therapy to analyze vascular dysfunction improvement.

RESULTS

Our results suggest that severe hepatic insulin resistance was expanded to cardiovascular tissues. This vascular insulin resistance observed in aorta artery from iLIRKO mice correlated with a reduction in both PI3K/AKT/eNOS and p42/44 MAPK pathways, and it might be implicated in their vascular alterations characterized by endothelial dysfunction, hypercontractility and eNOS/iNOS levels' imbalance. Finally, regarding long-term hepatic expression of IR isoforms, IRA was more efficient than IRB in the improvement of vascular dysfunction observed in iLIRKO mice.

CONCLUSION

Severe hepatic insulin resistance is sufficient to produce cardiovascular insulin resistance and dysfunction. Long-term hepatic expression of IRA restored the vascular damage observed in iLIRKO mice.

Non-Coding RNAs: Novel Players in Insulin Resistance and Related Diseases

The rising prevalence of metabolic diseases related to insulin resistance (IR) have stressed the urgent need of accurate and applicable tools for early diagnosis and treatment. In the last decade, non-coding RNAs (ncRNAs) have gained growing interest because of their potential role in IR modulation. NcRNAs are variable-length transcripts which are not translated into proteins but are involved in gene expression regulation. Thanks to their stability and easy detection in biological fluids, ncRNAs have been investigated as promising diagnostic and therapeutic markers in metabolic diseases, such as type 2 diabetes mellitus (T2D), obesity and non-alcoholic fatty liver disease (NAFLD). Here we review the emerging role of ncRNAs in the development of IR and related diseases such as obesity, T2D and NAFLD, and summarize current evidence concerning their potential clinical application.

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.

Metabolic Consequences of Neuronal HIF1α-Deficiency in Mediobasal Hypothalamus in Mice

OBJECTIVE

This study aims to investigate whether hypoxia-inducible factor 1α (HIF1α) in the neurons of the mediobasal hypothalamus is involved in the regulation of body weight, glucose, and lipid metabolism in mice and to explore the underlying molecular mechanisms.

METHODS

HIF1α ^flox/flox mice were used. The adeno-associated virus that contained either cre, GFP and syn, or GFP and syn (controls) was injected into the mediobasal hypothalamus to selectively knock out HIF1α in the neurons of the mediobasal hypothalamus. The body weight and food intake were weighed daily. The levels of blood glucose, insulin, total cholesterol (TC), triglyceride (TG), free fatty acid (FFA), high-density lipoprotein (HDL), and low-density lipoprotein (LDL)were tested. Intraperitoneal glucose tolerance test (IPGTT) was performed. The insulin-stimulated Akt phosphorylation in the liver, epididymal fat, and skeletal muscle were examined. Also, the mRNA expression levels of HIF1α, proopiomelanocortin (POMC), neuropeptide Y (NPY), and glucose transporter protein 4 (Glut4) in the hypothalamus were checked.

RESULTS

After selectively knocking out HIF1α in the neurons of the mediobasal hypothalamus (HIF1αKOMBH), the body weights and food intake of mice increased significantly compared with the control mice (p < 0.001 at 4 weeks). Compared with that of the control group, the insulin level of HIF1αKOMBH mice was 3.5 times higher (p < 0.01). The results of the IPGTT showed that the blood glucose level of the HIF1αKOMBH group at 20-120 min was significantly higher than that of the control group (p < 0.05). The serum TC, FFA, HDL, and LDL content of the HIF1αKOMBH group was significantly higher than those of the control group (p < 0.05). Western blot results showed that compared with those in the control group, insulin-induced AKT phosphorylation levels in liver, epididymal fat, and skeletal muscle in the HIF1αKOMBH group were not as significantly elevated as in the control group. Reverse transcription-polymerase chain reaction (RT-PCR) results in the whole hypothalamus showed a significant decrease in Glut4 mRNA expression. And the mRNA expression levels of HIF1α, POMC, and NPY of the HIF1αKOMBH group decreased significantly in ventral hypothalamus.

CONCLUSIONS

The hypothalamic neuronal HIF1α plays an important role in the regulation of body weight balance in mice under normoxic condition. In the absence of hypothalamic neuronal HIF1α, the mice gained weight with increased appetite, accompanied with abnormal glucose and lipid metabolism. POMC and Glut4 may be responsible for this effect of HIF1α.

Extracellular Vesicles-Mediated Transfer of miRNA Let-7b from PC3 Cells to Macrophages

Prostate-derived extracellular vesicles (pEVs) may represent a way to selectively transport cargo molecules from the producing cells to the target cells to allow biological events, both in physiological and pathological circumstances. pEVs cargo participates in the modulation of the inflammatory responses in physiological conditions and during cancer progression. In the present study, we examined the expression levels of miRNA Let-7b, in both precursor and mature forms, in noncancerous and cancerous prostate cell lines, PNT2 and PC3 respectively, and in their extracellular vesicles (EVs) using reverse-transcription quantitative PCR strategies. We showed that miRNA Let-7b was highly expressed in noncancerous cells and strongly decreased in cancerous PC3 cells, while the opposite was observed in the respective EVs, thus supporting the tumor suppressor role of miRNA Let7-b. We also demonstrated that miRNA Let-7b can be transferred to THP-1 cells via EVs, which are known to induce TAM-like polarization. Our results support the view that miRNA Let-7 b, contained in PC3-derived EVs, is associated with the increase in the miRNA Let7-b observed in TAM-like macrophages. Overall, our results indicate that circulating EV-loaded miRNA might be useful biomarkers for prostate cancer progression and might also support a possible use of pEVs as targets for prostate cancer therapy.