Challenges in Pharmacological Intervention in Perilipins (PLINs) to Modulate Lipid Droplet Dynamics in Obesity and Cancer

PLIN1 suppresses glioma progression through regulating lipid metabolism

Glioma is a common and destructive brain tumor, which is highly heterogeneous with poor prognosis. Developing diagnostic and prognostic markers to identify and treat glioma early would significantly improve the therapeutic outcomes. Here, we conducted RNA next-generation sequencing with 33 glioma samples and 15 normal brain samples. We found Perilipin 1 (PLIN1) downregulated in glioma and correlated with poorer outcome. Subsequent experiments revealed that up regulation of PLIN1 led to repressed cell growth and invasion in glioma. Moreover, overexpression of PLIN1 increased lipid accumulation in glioma cells, with increasing expression of lipid biosynthesis related genes and decreasing expression of lipolysis related genes. Mechanically, we revealed that the PI3K/AKT axis could regulate PLIN1 levels in glioma, that inhibition of the activity of PI3K/AKT axis could increase PLIN1 levels in glioma. In conclusion, the dysregulation PI3K/AKT axis led to PLIN1 downregulation and the following tumor proliferation, invasion and lipid metabolism reprogramming in glioma.

Omics Approaches to Study Perilipins and Their Significant Biological Role in Cardiometabolic Disorders

Lipid droplets (LDs), highly dynamic cellular organelles specialized in lipid storage and maintenance of lipid homeostasis, contain several proteins on their surface, among which the perilipin (Plin) family stands out as the most abundant group of LD-binding proteins. They play a pivotal role in influencing the behavior and functionality of LDs, regulating lipase activity, and preserving a balance between lipid synthesis and degradation, which is crucial in the development of obesity and abnormal accumulation of fat in non-adipose tissues, causing negative adverse biological effects, such as insulin resistance, mitochondrial dysfunction, and inflammation. The expression levels of Plins are often associated with various diseases, such as hepatic steatosis and atherosclerotic plaque formation. Thus, it becomes of interest to investigate the Plin roles by using appropriate "omics" approaches that may provide additional insight into the mechanisms through which these proteins contribute to cellular and tissue homeostasis. This review is intended to give an overview of the most significant omics studies focused on the characterization of Plin proteins and the identification of their potential targets involved in the development and progression of cardiovascular and cardiometabolic complications, as well as their interactors that could be useful for more efficient therapeutic and preventive approaches for patients.

Zearalenone exacerbates lipid metabolism disorders by promoting liver lipid droplet formation and disrupting gut microbiota

Zearalenone (ZEA), produced by Fusarium, is a fungal toxin commonly found in maize, wheat, and other cereals. ZEA has the ability to bind to estrogen receptors of humans and animals and is an environmental endocrine disruptor that may interfere with glucose homeostasis and lipid metabolism. In this study, we first investigated the effects of chronic exposure to low doses of ZEA with a high-fat-diet (HFD) in obese C57BL/6 J mice. In the absence of significant toxicity and without affecting glucose tolerance, 50 and 100 μg/kg b. w. ZEA was found to significantly exacerbate lipid synthesis, accumulation and alter the overall transcriptional profile of the liver in mice synergistically with HFD. Validation in combination with AML-12 cells revealed that ZEA promoted lipid synthesis and increased hepatic lipid droplet accumulation via the HNF1β/PPARγ and SREBP1c-HSD17B13/PLINs signal pathways. Further, by analyzing the changes in the intestinal flora of mice and their relationship with lipid metabolism genes, it was found that ZEA decreased the relative abundance of Lactobacillus and increased the relative abundance of Ileococcus, E. faecalis, and Ricardia. These changes were significantly correlated with the expression of Pparg and Srebf1, etc. ZEA may contribute to the abnormality of lipid metabolism by influencing the intestinal microbiota. This study highlights the synergistic effects of long-term low-dose ZEA and excess lipids, providing a theoretical basis for elucidating the mechanism of chronic toxicity of ZEA and its negative impact on metabolic diseases.

Liraglutide reduces bone marrow adipogenesis by miR-150-5p/ GDF11 axis in diabetic rats

In recent years, a common-used antidiabetic drug, liraglutide, was identified with extra effects on lipid metabolism. Its effects against excessive lipid deposition in bone marrow were gained much attention but not well established. Our aim in the present study is to explore the interaction of miRNAs-mRNAs altered by liraglutide administration during bone marrow adipogenesis in diabetes. To establish the diabetic animal model, rats were treated with high fat diet (HFD) and STZ injection. We then identified the lowering effect of liraglutide on lipids metabolism in the diabetes. During this process, high-throughput sequencing and bioinformatics analyses on miRNAs extracted from bone marrow mesenchymal stem cells (BMSCs) were conducted after liraglutide administration. We then identified five differentially expressed miRNAs (miRNA-150-5p, miRNA-129-5p, miRNA-201-3p, miRNA-201-5p, and miRNA-214-5p). The expressions of the DE miRNAs were verified as temporal specific expression patterns in Day 3 and in Day 7. Among them, miRNA-150-5p expression was more stable and consistent with the sequencing data. Of interest, miR-150-5p overexpression facilitated adipogenesis of BMSCs. But this promotion was alleviated by liraglutide. The predicted target gene of miR-150-5p, GDF11, was validated to be involved in liraglutide alleviated BMSCs' lipid accumulation in diabetes. In vitro, liraglutide increased the GDF11 expression, rescued its down-expression by siGDF11 and inhibit the adipogenesis of BMSCs cultured in high glucose medium. In vivo, liraglutide reversed the HFD-STZ induced excessive lipid droplets by up-regulation of GDF11 expression, which was discounted by agomiR-150-5p injection. Above all, liraglutide might alleviate bone marrow fat accumulation via inactivating miR-150-5p/GDF11 axis in diabetes.

Decreased skeletal muscle intramyocellular lipid droplet-mitochondrial contact contributes to myosteatosis in cancer cachexia

Cancer cachexia, the unintentional loss of lean mass, contributes to functional dependency, poor treatment outcomes, and decreased survival. Although its pathogenicity is multifactorial, metabolic dysfunction remains a hallmark of cachexia. However, significant knowledge gaps exist in understanding the role of skeletal muscle lipid metabolism and dynamics in this condition. We examined skeletal muscle metabolic dysfunction, intramyocellular lipid droplet (LD) content, LD morphology and subcellular distribution, and LD-mitochondrial interactions using the Lewis lung carcinoma (LLC) murine model of cachexia. C57/BL6 male mice (n = 20) were implanted with LLC cells (106) in the right flank or underwent PBS sham injections. Skeletal muscle was excised for transmission electron microscopy (TEM; soleus), oil red O/lipid staining [tibialis anterior (TA)], and protein (gastrocnemius). LLC mice had a greater number (232%; P = 0.006) and size (130%; P = 0.023) of intramyocellular LDs further supported by increased oil-red O positive (87%; P = 0.0109) and "very high" oil-red O positive (178%; P = 0.0002) fibers compared with controls and this was inversely correlated with fiber size (R2 = 0.5294; P < 0.0001). Morphological analyses of LDs show increased elongation and complexity [aspect ratio: intermyofibrillar (IMF) = 9%, P = 0.046) with decreases in circularity [circularity: subsarcolemmal (SS) = 6%, P = 0.042] or roundness (roundness: whole = 10%, P = 0.033; IMF = 8%, P = 0.038) as well as decreased LD-mitochondria touch (-15%; P = 0.006), contact length (-38%; P = 0.036), and relative contact (86%; P = 0.004). Furthermore, dysregulation in lipid metabolism (adiponectin, CPT1b) and LD-associated proteins, perilipin-2 and perilipin-5, in cachectic muscle (P < 0.05) were observed. Collectively, we provide evidence that skeletal muscle myosteatosis, altered LD morphology, and decreased LD-mitochondrial interactions occur in a preclinical model of cancer cachexia.NEW & NOTEWORTHY We sought to advance our understanding of skeletal muscle lipid metabolism and dynamics in cancer cachexia. Cachexia increased the number and size of intramyocellular lipid droplets (LDs). Furthermore, decreases in LD-mitochondrial touch, contact length, and relative contact along with increased LD shape complexity with decreases in circularity and roundness. Dysregulation in lipid metabolism and LD-associated proteins was also documented. Collectively, we show that myosteatosis, altered LD morphology, and decreased LD-mitochondrial interactions occur in cancer cachexia.

Exploring the impact of lipid droplets on the evolution and progress of hepatocarcinoma

Over the past 10 years, the biological role of lipid droplets (LDs) has gained significant attention in the context of both physiological and pathological conditions. Considerable progress has been made in elucidating key aspects of these organelles, yet much remains to be accomplished to fully comprehend the myriad functions they serve in the progression of hepatic tumors. Our current perception is that LDs are complex and active structures managed by a distinct set of cellular processes. This understanding represents a significant paradigm shift from earlier perspectives. In this review, we aim to recapitulate the function of LDs within the liver, highlighting their pivotal role in the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) (Hsu and Loomba, 2024) and their contribution to the progression towards more advanced pathological stages up to hepatocellular carcinoma (HC) (Farese and Walther, 2009). We are aware of the molecular complexity and changes occurring in the neoplastic evolution of the liver. Our attempt, however, is to summarize the most important and recent roles of LDs across both healthy and all pathological liver states, up to hepatocarcinoma. For more detailed insights, we direct readers to some of the many excellent reviews already available in the literature (Gluchowski et al., 2017; Hu et al., 2020; Seebacher et al., 2020; Paul et al., 2022).

Lipid droplets in pathogen infection and host immunity

As the hub of cellular lipid metabolism, lipid droplets (LDs) have been linked to a variety of biological processes. During pathogen infection, the biogenesis, composition, and functions of LDs are tightly regulated. The accumulation of LDs has been described as a hallmark of pathogen infection and is thought to be driven by pathogens for their own benefit. Recent studies have revealed that LDs and their subsequent lipid mediators contribute to effective immunological responses to pathogen infection by promoting host stress tolerance and reducing toxicity. In this comprehensive review, we delve into the intricate roles of LDs in governing the replication and assembly of a wide spectrum of pathogens within host cells. We also discuss the regulatory function of LDs in host immunity and highlight the potential for targeting LDs for the diagnosis and treatment of infectious diseases.

Clinically Effective Molecules of Natural Origin for Obesity Prevention or Treatment

The prevalence and incidence of obesity and the comorbidities linked to it are increasing worldwide. Current therapies for obesity and associated pathologies have proven to cause a broad number of adverse effects, and often, they are overpriced or not affordable for all patients. Among the alternatives currently available, natural bioactive compounds stand out. These are frequently contained in pharmaceutical presentations, nutraceutical products, supplements, or functional foods. The clinical evidence for these molecules is increasingly solid, among which epigallocatechin-3-gallate, ellagic acid, resveratrol, berberine, anthocyanins, probiotics, carotenoids, curcumin, silymarin, hydroxy citric acid, and α-lipoic acid stand out. The molecular mechanisms and signaling pathways of these molecules have been shown to interact with the endocrine, nervous, and gastroenteric systems. They can regulate the expression of multiple genes and proteins involved in starvation-satiety processes, activate the brown adipose tissue, decrease lipogenesis and inflammation, increase lipolysis, and improve insulin sensitivity. This review provides a comprehensive view of nature-based therapeutic options to address the increasing prevalence of obesity. It offers a valuable perspective for future research and subsequent clinical practice, addressing everything from the molecular, genetic, and physiological bases to the clinical study of bioactive compounds.