Antagonizing adipose tissue-derived exosome miR-103-hepatocyte phosphatase and tensin homolog pathway alleviates autophagy in non-alcoholic steatohepatitis: A trans-cellular crosstalk

Roles of extracellular vesicles from different origins in metabolic-associated fatty liver disease: progress and perspectives

Metabolic-Associated Fatty Liver Disease (MAFLD) is the most common chronic liver disease worldwide, associated with systemic metabolic dysregulation. It can progress from simple hepatic steatosis (MAFL) to more severe conditions like Metabolic-Associated Steatohepatitis (MASH), fibrosis, cirrhosis, and Hepatocellular Carcinoma (HCC). There is a critical lack of reliable non-invasive diagnostic methods and effective pharmaceutical treatments for MAFLD/MASH, emphasizing the need for further research. Extracellular vesicles (EVs) are nanoscale structures that play important roles in cell signaling by delivering bioactive molecules. However, there is a significant gap in literature regarding the roles of EVs from hosts, plants, and microbiota in MAFLD. This review explores the potential of EVs from various sources-host, plants, and microbiota-as biomarkers, therapeutic agents, drug carriers, and treatment targets for MAFLD. Firstly, the roles of host-derived extracellular vesicles (EVs) in MAFLD, with a focus on cell-type specific EVs and their components-proteins, miRNAs, and lipids-for disease diagnosis and monitoring were discussed. Moreover, it highlighted the therapeutic potential of mesenchymal stem cell (MSC)-derived EVs in reducing lipid accumulation and liver injury, and immune cell-derived EVs in mitigating inflammation and fibrosis. The review also discussed the use of host-derived EVs as drug carriers and therapeutic targets due to their ability to deliver bioactive molecules that impact disease mechanisms. Additionally, it summarized research on plant-derived EVs, which help reduce liver lipid accumulation, inflammation, and enhance gut barrier function in MAFLD. Also, the review explored microbial-derived EVs as novel therapeutic targets, particularly in relation to insulin resistance, liver inflammation, and dysfunction in MAFLD. Overall, by exploring the diverse roles of EVs from host, plant, and microbiota sources in MAFLD, this review offers valuable insights into their potential as non-invasive biomarkers and novel therapeutic strategies, which could pave the way for more effective diagnostic and treatment options for this increasingly prevalent liver disease. Notably, the challenges of translating EVs into clinical practice were also thoroughly discussed, aiming to provide possible directions and strategies for future research.

Extracellular vesicle-mediated bidirectional communication between the liver and other organs: mechanistic exploration and prospects for clinical applications

The liver, functioning as an endocrine organ, secretes a variety of substances that influence the activities of other body organs. Conversely, molecules generated by organs such as bone, the gut, and adipose tissue can also impact liver function. Accumulating evidence suggests bidirectional communication between the liver and other organs. However, research on how extracellular vesicles (EVs), which transport active molecular mediators, contribute to this interorgan communication is still in its nascent stages. EVs are capable of transporting functional molecules, including lipids, nucleic acids, and proteins, thereby affecting recipient cells across different organs at the biological level. This review examines the role of EVs in facilitating bidirectional communication between the liver and other organs such as bone, the cardiovascular system, the gut, the pancreas, the brain, the lungs, the kidneys, and adipose tissue. It explores their potential in disease treatment and highlights the challenges in understanding EV-mediated interorgan interactions. The contribution of mediator-carrying EVs to two-way communication between the liver and other organs remains an area of ongoing investigation. Future research will provide a more comprehensive theoretical foundation to clarify the precise mechanisms governing communication between the liver and other organs, pinpoint medical targets, and expand the application of EVs within the realm of precision medicine.

Obesity and Adipose-Derived Extracellular Vesicles: Implications for Metabolic Regulation and Disease

Obesity, a global epidemic, is a major risk factor for chronic diseases such as type 2 diabetes, cardiovascular disorders, and metabolic syndrome. Adipose tissue, once viewed as a passive fat storage site, is now recognized as an active endocrine organ involved in metabolic regulation and inflammation. In obesity, adipose tissue dysfunction disrupts metabolic balance, leading to insulin resistance and increased production of adipose-derived extracellular vesicles (AdEVs). These vesicles play a key role in intercellular communication and contribute to metabolic dysregulation, affecting organs such as the heart, liver, and brain. AdEVs carry bioactive molecules, including microRNAs, which influence inflammation, insulin sensitivity, and tissue remodeling. In the cardiovascular system, AdEVs can promote atherosclerosis and vascular dysfunction, while those derived from brown adipose tissue offer cardioprotective effects. In type 2 diabetes, AdEVs exacerbate insulin resistance and contribute to complications such as diabetic cardiomyopathy and cognitive decline. Additionally, AdEVs are implicated in metabolic liver diseases, including fatty liver disease, by transferring inflammatory molecules and lipotoxic microRNAs to hepatocytes. These findings highlight the role of AdEVs in obesity-related metabolic disorders and their promise as therapeutic targets for related diseases.

Adipose-derived exosomes ameliorate skeletal muscle atrophy via miR-146a-5p/IGF-1R signaling

The study of muscle disorders has gained popularity, with a particular emphasis on the relationship between adipose tissue and skeletal muscle. In our investigation, we discovered that the deletion of miR-146a-5p specifically in adipose tissue (aKO) led to a notable rise in mice's mass and adiposity. In contrast, it led to a decline in lean mass, ability to exercise, diameter of muscle fibers, and the levels of genes associated with differentiation. The co-culture experiment showed that the transfection of miR-146a-5p mimics to 3T3-L1 significantly suppressive cell growth and promotes myotube differentiation in C2C12 cells. Exosomes from white adipose tissue (WAT) of aKO mice (aKO-WAT-Exos) significantly promoted muscle atrophy and inhibited differentiation of C2C12 cells but were reversed by co-incubation with miR-146a-5p-mimics. The miR-146a-5p can specifically target IGF-1R to improve skeletal muscle wasting. In this process, the PI3K/AKT/mTOR pathway is activated or the FoxO3 pathway is inhibited to enhance the synthesis of skeletal muscle proteins. Significantly, miR-146a-5p serves a crucial function as a microRNA in the communication of the fat-muscle connection. It can be transported through the pathway of exosomes derived from adipose tissue, ultimately ameliorating skeletal muscle atrophy and modulating body mass index (BMI).

Adipose-derived extracellular vesicles - a novel cross-talk mechanism in insulin resistance, non-alcoholic fatty liver disease, and polycystic ovary syndrome

Obesity is the best described risk factor for the development of non-alcoholic fatty liver disease (NAFLD)/metabolic dysfunction associated steatotic liver disease (MASLD) and polycystic ovary syndrome (PCOS) while the major pathogenic mechanism linking these entities is insulin resistance (IR). IR is primarily caused by increased secretion of proinflammatory cytokines, adipokines, and lipids from visceral adipose tissue. Increased fatty acid mobilization results in ectopic fat deposition in the liver which causes endoplasmic reticulum stress, mitochondrial dysfunction, and oxidative stress resulting in increased cytokine production and subsequent inflammation. Similarly, IR with hyperinsulinemia cause hyperandrogenism, the hallmark of PCOS, and inflammation in the ovaries. Proinflammatory cytokines from both liver and ovaries aggravate IR thus providing a complex interaction between adipose tissue, liver, and ovaries in inducing metabolic abnormalities in obese subjects. Although many pathogenic mechanisms of IR, NAFLD/MASLD, and PCOS are known, there is still no effective therapy for these entities suggesting the need for further evaluation of their pathogenesis. Extracellular vesicles (EVs) represent a novel cross-talk mechanism between organs and include membrane-bound vesicles containing proteins, lipids, and nucleic acids that may change the phenotype and function of target cells. Adipose tissue releases EVs that promote IR, the development of all stages of NAFLD/MASLD and PCOS, while mesenchymal stem cell-derived AVs may alleviate metabolic abnormalities and may represent a novel therapeutic device in NAFLD/MASLD, and PCOS. The purpose of this review is to summarize the current knowledge on the role of adipose tissue-derived EVs in the pathogenesis of IR, NAFLD/MASLD, and PCOS.