Too much or too less lipid deposition increases mortality, while in contrast, modest lipid deposition during aging is crucial for healthspan. How animals determine the aging state and then promote appropriate lipid deposition for lifespan benefits are largely unknown. In this study, we identified citrulline as a key metabolite driving aging-related lipid deposition for healthspan in Caenorhabditis elegans. Citrulline deficiency reduced aging-related lipid accumulation and shortened lifespan, an effect reversible by dietary supplementation. Mechanistically, during aging, the transcription factor MXL-3 is activated to upregulate the expression of pyr-1, encoding ornithine transcarbamylase (OTC), for the production of citrulline, which then activates the lipogenic enzymes DGAT-2 and MBOA-2 to consequently promote lipid synthesis and deposition for lifespan extension. Collectively, we uncover a MXL-3-citrulline-lipogensis axis to ensure healthspan, providing distinct insights into metabolic aging.

Dietary cholesterol and de novo cholesterol synthesis in the liver use reciprocal coordination to maintain cholesterol homeostasis. However, high level of dietary cholesterol still promotes excessive cholesterol accumulation in the liver, leading to metabolic dysfunction-associated steatohepatitis (MASH), yet the mechanisms remain poorly understood. Here we show that hepatic S100A11, a member of the S100 family of calcium-binding proteins, positively responds to the dietary cholesterol level and is involved in hepatic cholesterol metabolism. S100A11 localizes to the endoplasmic reticulum and can bind to cholesterol. In vivo and in vitro, hepatic overexpression of S100A11 led to SREBP2 activation to promote cholesterol synthesis, uptake, and accumulation, consequently exacerbating steatohepatitis. In contrast, inactivation of S100A11 had opposite effects and improved steatohepatitis. Mechanistically, S100A11 triggers the non-canonical entry of SREBP2 into the nucleus through a S100A11-ANXA1-KPNB axis, distinct from the well-known INSIG-SCAP pathway or Caspase2 pathways. Therefore, our work identifies S100A11 as a regulator of liver cholesterol metabolism, providing a promising target to treat MASH and hypercholesterolemia.

OBJECTIVE:Global growth hormone receptor knockout (GHR-/-) extends lifespan but also causes adverse effects. As a key target of growth hormone (GH), adipose tissue may mediate aging, though the underlying mechanisms remain unclear. We investigated how adipose-specific GHR ablation influences multisystem aging, with a focus on metabolic health and cognitive function. METHODS:We generated adipose-specific GHR knockout (Ad-GHRKO) mice and assessed healthspan parameters including cognitive function, musculoskeletal integrity and metabolic profiles. Adipose tissue remodelling and inflammation were examined by histology and protein analysis. Subcutaneous white adipose transcriptomics identified gene expression changes. The role of the AMPK-SIRT1-Ac-PPARγ pathway in metabolic elasticity and aging was elucidated by Western blot and in vitro assays. RESULTS:Ad-GHRKO mice exhibited extended healthspan, with enhanced cognitive performance, improved muscle strength and bone mass and a lifespan increase trend. Mechanistically, GHR ablation remodelled adipose tissue, reducing age-related lipid redistribution, restoring glucose homeostasis and creating a low-inflammation, high-plasticity depot. This reprogramming boosted systemic metabolic elasticity primarily via AMPK-SIRT1-Ac-PPARγ activation. AMPK inhibition abolished benefits, confirming its pivotal role. CONCLUSION:Our findings identify adipose-specific GH signalling antagonism as a regulatory switch that recalibrates the local balance between GH and IGF-1 actions, thereby reprogramming adipose tissue to promote coordinated systemin metabolic resilience during aging. This tissue-targeted strategy circumvents the developmental and endocrine limitations associated with global GH/IGF-1 suppression. Rather than merely extending lifespan, adipose-specific GHR ablation supports healthier aging by preserving metabolic homeostasis, maintaining multisystem functional integrity and reducing age-associated inflammatory and fibrotic remodelling. Collectively, these results highlight a potentially translatable approach for mitigating age-related metabolic and cognitive decline.

Pancreatic cancer remains a highly lethal malignancy with limited treatment options. Given the versatile bioactivity of quinazoline derivatives, which are regarded as a promising scaffold for anticancer drug discovery, we designed and synthesized a series of novel quinazoline analogues. Their cytotoxicity was evaluated in three pancreatic cancer cell lines (HPAC, AsPC-1, and MIA PaCa-2), leading to the identification of compound 5a, which exhibited potent effects across all tested cell lines. Further investigation of anticancer activity indicated that 5a significantly inhibited DNA synthesis, clonogenesis, and migration in MIA PaCa-2 cells. Mechanism study revealed that 5a disrupted autophagy, as evidenced by downregulation of Beclin-1 expression and accumulation of LC3B-II and p62, through a mechanism independent of the canonical AMPK-mTOR-ULK1 signaling pathway. This study provides a promising active scaffold for the development of anti-pancreatic cancer agents.

Lipid droplets (LDs) are intracellular organelles that dynamically regulate lipid and energy homeostasis, mediate hormone production, produce inflammation signaling, while also participating in numerous biological processes and activities. Dysregulation of LD homeostasis is linked to various diseases, such as lipodystrophy, obesity, type 2 diabetes (T2D), cardiovascular diseases (CVD), metabolic dysfunction-associated steatotic liver disease (MASLD), neuronal diseases, and among others. The core of LDs consists of neutral lipids, including triacylglycerol (TAG), cholesteryl esters (CE), and retinyl esters (RE), which are encircled by a monolayer of phospholipid membrane decorated with a subset of LD proteins, both resident as well as dynamic, that vary in different cells, tissues, organs, and organisms. Over the past two decades, together with technological advances, significant achievements have been made in understanding LD biology, including their lifecycle: such as biogenesis, growth/expansion, fusion, and degradation, as well as their diversity and heterogeneity, under both physiological and pathological conditions. In this review, we summarize the current knowledge and methodologies of LD biology in animal cells, and also provide guiding questions, hopefully bringing new directions for future study of LDs and for potential therapeutic treatments for LD-related human diseases.

BackgroundLiver cancer remains a major global health burden, with hepatocellular carcinoma (HCC) accounting for approximately 80% of liver cancer cases. Cancer stem cells (CSCs) play a critical role in HCC initiation, progression, metastasis, and resistance to therapy, making them critical targets for novel therapeutic interventions. However, effective agents specifically targeting CSCs in HCC remain limited. The objective of this study was to identify and characterize novel small molecules that inhibit CSCs properties and overcome drug resistance in HCC.MethodsFunctional assays assessed the effects of C504244 on tumor sphere formation, cancer cell proliferation, and migration. RNA sequencing was conducted on C504244-treated HCC cells to investigate changes in gene expression profiles. Downstream targets of the Wnt signaling pathway were analyzed to determine pathway inhibition. Co-immunoprecipitation (Co-IP) was performed to assess whether C504244 disrupts the interaction between β-catenin and Transcription Factor 4 (TCF4) in HCC cells. Lenvatinib-resistant HCC cell lines were used to evaluate the combinatorial efficacy of C504244 and Lenvatinib in vitro and in vivo.ResultsC504244 significantly suppressed tumor sphere formation, proliferation, and migration of HCC cells. Transcriptome analysis revealed that C504244 treatment led to significant inhibition of the Wnt signaling pathway, with corresponding downregulation of downstream target gene expression. Mechanistically, C504244 disrupted the β-catenin/TCF4 complex formation, which may contribute to reduced transcriptional activity. Since β-catenin signaling is hyperactivated in Lenvatinib-resistant HCC cells, C504244 was tested in combination with Lenvatinib and found to markedly sensitize these resistant cells to Lenvatinib treatment both in vitro and in vivo.ConclusionsC504244 represents a promising agent that effectively inhibits β-catenin signaling, thereby impairing CSCs properties and reversing Lenvatinib resistance in HCC cells. These findings suggest that C504244 may serve as a potential therapeutic agent for HCC.

Impaired glucose-stimulated insulin secretion (GSIS) is a hallmark of β cell dysfunction in diabetes. Epigenetic mechanisms govern cellular glucose sensing and GSIS by β cells, but they remain incompletely defined. Here, we found that BAF60a functions as a chromatin regulator that sustains biphasic GSIS and preserves β cell function under metabolic stress conditions. BAF60a was downregulated in β cells from obese and diabetic mice, monkeys, and humans. β cell-specific inactivation of BAF60a in adult mice impaired GSIS, leading to hyperglycemia and glucose intolerance. Conversely, restoring BAF60a expression improved β cell function and systemic glucose homeostasis. Mechanistically, BAF60a physically interacted with Nkx6.1 to selectively modulate chromatin accessibility and transcriptional activity of target genes critical for GSIS coupling in islet β cells. A BAF60a V278M mutation associated with decreased β cell GSIS function was identified in human donors. Mice carrying this mutation, which disrupted the interaction between BAF60a and Nkx6.1, displayed β cell dysfunction and impaired glucose homeostasis. In addition, GLP-1R and GIPR expression was significantly reduced in BAF60a-deficient islets, attenuating the insulinotropic effect of GLP-1R agonists. Together, these findings support a role for BAF60a as a component of the epigenetic machinery that shapes the chromatin landscape in β cells critical for glucose sensing and insulin secretion.

Metabolic dysfunction-associated fatty liver disease (MAFLD) has become the most prevalent chronic liver disease worldwide, affecting both obese and non-obese individuals. While the reduced levels of circulating growth hormone (GH) and insulin-like growth factor 1 (IGF-1) have been consistently observed in patients with hepatic steatosis, the molecular role of hepatic growth hormone receptor (GHR) in MAFLD pathogenesis remains unclear. In this study, we established a liver-specific Ghr knockout (LGHRKO) mouse model that faithfully recapitulates non-obese MAFLD, characterized by hepatomegaly, elevated serum lipids and transaminases, and pronounced hepatic lipid accumulation, all occurring in the absence of obesity or increased adiposity. Mechanistically, LGHRKO livers displayed enhanced lipogenesis, impaired lipolysis, and upregulated cluster of differentiation 36 (CD36) expression, thereby driving hepatic lipid deposition. Single-cell RNA sequencing (scRNA-seq) further revealed hepatocyte-specific transcriptional alterations, including activation of lipid metabolic pathways and dysregulation of autophagy-related processes, providing insights into the cellular mechanisms underlying disease progression. Complementary human genetic analyses, including two-sample Mendelian randomization (MR) and genome-wide association studies (GWASs), demonstrated a causal relationship between impaired GH-IGF signaling and susceptibility to MAFLD, thereby bridging experimental observations with human disease risk. Collectively, our findings identify hepatic GHR deficiency as a key driver of non-obese MAFLD, establish LGHRKO mice as a valuable model for mechanistic and therapeutic studies, and underscore the translational significance of GH-IGF signaling in metabolic liver disease.

n-3 PUFAs possess numerous health benefits. The FAT-1 desaturase in the model organism Caenorhabditis elegans is a Δ15-desaturase that converts n-6 PUFAs into n-3 PUFAs. Transgenic expression of FAT-1 has been used in organisms, such as pigs, mice, and fish, to improve n-3 PUFA levels. However, the determination of FAT-1 activity and substrate preference per se remains unclear. AlphaFold structure prediction revealed that FAT-1 is an integral membrane protein located in the endoplasmic reticulum, and it consists of four transmembrane helices (1-4) with a functional CYTB5 domain in the N terminus and a desaturase domain containing three histidine-rich sequences (His boxes) in the C terminus. A small region in the desaturase domain containing amino acids 210-217, especially G212, G216, and S217, is essential for its activity. FAT-1 can convert all four n-6 PUFAs to corresponding or downstream n-3 PUFAs in both C. elegans and mammalian cells and may prioritize the conversion of C20:4n6 (arachidonic acid) to C20:5n3 (EPA). These results uncover the significant mechanism of the activity and substrate preference of the FAT-1 desaturase, providing insights into the transgenic application of FAT-1.

The abnormal function of histone lysine demethylase 6B (KDM6B) is closely associated with the development and progression of various human diseases, including cancer, inflammatory disorders, and psychiatric conditions, supporting KDM6B as a significant therapeutic target. However, the development of potent and selective KDM6B inhibitors remains a critical unmet need. Based on the hit compound (A01) discovered by enzyme-level screening, a series of derivatives with quinazoline scaffold were designed, synthesized and identified as KDM6B inhibitors. Among these, compound 13k exhibited optimal potency (IC50 = 1.8 μM) with superior selectivity over other JMJD subfamily members. Furthermore, 13k upregulates histone methylation levels in THP-1 cells, highlighting its functional effect in a cellular context. This study provides a promising scaffold for developing selective KDM6B inhibitors, as well as delivers a tool compound for probing the biological functions of KDM6B. These findings offer a potential lead for future KDM6B-targeted drug discovery.

Cholesterol is an essential lipid molecule in mammalian cells. It is not only involved in the formation of cell membranes but also serves as a raw material for the synthesis of bile acids, vitamin D, and steroid hormones. Additionally, it acts as a covalent modifier of proteins and plays a crucial role in numerous life processes. Generally, the metabolic processes of cholesterol absorption, synthesis, conversion, and efflux are strictly regulated. Excessive accumulation of cholesterol in the body is a risk factor for metabolic diseases such as cardiovascular disease, type 2 diabetes, and metabolic dysfunction-associated steatotic liver disease (MASLD). In this review, we first provide an overview of the discovery of cholesterol and the fundamental process of cholesterol metabolism. We then summarize the relationship between dietary cholesterol intake and the risk of developing MASLD, and also the animal models of MASLD specifically established with a cholesterol-containing diet. In the end, the role of cholesterol-induced inflammation in the initiation and development of MASLD is discussed.

Histone lysine demethylase 4D (KDM4D) is a critical player in the regulation of tumorigenesis, emerging as a potential target for developing anti-tumor agents. In this study, a series of KDM4D inhibitors containing the 4,6-diarylquinoxaline scaffold were prepared based on the previously discovered hit compound QD-1. Among these inhibitors, 33a was the most potent compound, with an IC50 value of 0.62 μM. In an in vitro assay, 33a showed a superior ability to inhibit the viability of liver cancer Huh-7 cells with IC50 = 5.23 μM. 33a exhibits significant effects in inhibiting cell cycle progression and proliferation of liver cancer cells, as well as suppressing cell migration. This work provided a promising scaffold for developing KDM4D inhibitors, as well as a lead compound for the development of anti-tumor drugs targeting KDM4D.

Lipid droplets (LDs) are composed of a core of neutral lipids wrapped by a phospholipid (PL) monolayer containing several hundred proteins that vary between different cells or organisms. How LD proteins target to LDs is still largely unknown. Here, we show that RNAi knockdown or gene mutation of let-767, encoding a member of hydroxysteroid dehydrogenase (HSD), displaced the LD localization of three well-known LD proteins: DHS-3 (dehydrogenase/reductase), PLIN-1 (perilipin), and DGAT-2 (diacylglycerol O-acyltransferase 2), and also prevented LD growth in Caenorhabditis elegans. LET-767 interacts with ARF-1 (ADP-ribosylation factor 1) to prevent ARF-1 LD translocation for appropriate LD protein targeting and lipid homeostasis. Deficiency of LET-767 leads to the release of ARF-1, which further recruits and promotes translocation of ATGL-1 (adipose triglyceride lipase) to LDs for lipolysis. The displacement of LD proteins caused by LET-767 deficiency could be reversed by inhibition of either ARF-1 or ATGL-1. Our work uncovers a unique LET-767 for determining LD protein targeting and maintaining lipid homeostasis.

The superfamily of hydroxysteroid dehydrogenases (HSDs) has been well-characterized as enzymes in lipid metabolism, and especially in steroid hormone metabolism from bacteria to mammals. Recently, a subset of HSDs members, including 3β-HSD, 11β-HSD, and 17β-HSD, have been shown to be lipid droplet (LD)-associated proteins that are involved in LD dynamics beyond their canonical functions. This review summarizes current understanding of these LD-associated HSD proteins, focusing on how they regulate different LDs with respect to distinct neutral lipids including triacylglycerols (TAGs), cholesterol esters (CEs), and retinyl esters (REs), the evolutionally conserved role of some LD-associated 17β-HSDs in preventing lipolysis, and specific targeting of HSDs for the treatment of metabolic diseases and viral infections.

The insulin receptor (INSR, IR) has two isoforms, IRA and IRB, through alternative splicing. However, their distinct functions in vivo remain unclear. Here we generated β cell-specific IRB knockout (KO) mice (βIRBKO). The KO mice displayed worsened hyperinsulinemia and hyperproinsulinemia in diet-induced obesity due to impaired proinsulin processing in β cells. Mechanistically, loss of IRB suppresses eukaryotic translation initiation factor 4G1 (eIF4G1) by stabilizing the transcriptional receptor sterol-regulatory element binding protein 1 (SREBP1). Moreover, excessive autocrine proinsulin in βIRBKO mice enhances the activity of extracellular signal-regulated kinase (ERK) through the remaining IRA to further stabilize nuclear SREBP1, forming a feedback loop. Collectively, our study paves the way to dissecting the isoform-specific function of IR in vivo and highlights the important roles of IRB in insulin processing and protecting β cells from lipotoxicity in obesity.

The NLRP3 inflammasome plays an important role in protecting the host from infection and aseptic inflammation, and its regulatory mechanism is not completely understood. Dysregulation of NLRP3 can cause diverse inflammatory diseases. HECTD3 is a E3 ubiquitin ligase of the HECT family that has been reported to participate in autoimmune and infectious diseases. However, the relationship between HECTD3 and the NLRP3 inflammasome has not been well studied. Herein, we show that HECTD3 blocks the interaction between NEK7 and NLRP3 to inhibit NLRP3 inflammasome assembly and activation. In BMDMs, Hectd3 deficiency promotes the assembly and activation of NLRP3 inflammasome and the secretion of IL-1β, while the overexpression of HECTD3 inhibits these processes. Unexpectedly, HECTD3 functions in an E3 activity independent manner. Mechanically, the DOC domain of HECTD3 interacts with NACHT/LRR domain of NLRP3, which blocks NLRP3-NEK7 interaction and NLRP3 oligomerization. Furthermore, HECTD3 inhibits monosodium urate crystals (MSU)-induced gouty arthritis, a NLRP3-related disease. Thus, we reveal a novel regulatory mechanism of NLRP3 by HECTD3 and suggest HECTD3 could be a potential therapeutic target for NLRP3-dependent pathologies.

Drug-based backboned polymers, especially poly(drug monomer) cross-linked with dynamic chemical bonds, have emerged as nanomedicines with reduced excipients. In this research, rosmarinic acid, a natural antioxidant with therapeutic potential for acute liver injury, was polymerized through borated ester bonds, and the linear poly(rosmarinic acid) (PRA) self-assembled into nanomedicines (named PRA NPs) through hydrophobic interactions in the presence of hydrophobic glycerol monooleate. Due to the fast and efficient liver accumulation, PRA NPs increased the antioxidation potential of rosmarinic acid and demonstrated better therapeutic effects in the in vivo treatment of acute liver injury. The findings of this study indicate that borate ester bond-mediated backbone poly(drug monomer) polymeric nanomedicines could provide a new approach for the processing of versatile nanomedicines.