Aberrant hyper-expression of the RNA binding protein GIGYF2 in endothelial cells modulates vascular aging and function

Targeting endothelial cells: A novel strategy for pulmonary fibrosis treatment

Endothelial cells (ECs) are a monolayer of flat cells lining the inner surfaces of blood and lymphatic vessels. They play a key role in many physiological and pathological processes. Specifically, they maintain vascular permeability and structural stability and participate in immune responses, inflammation, coagulation, and other vital functions. ECs play a decisive role in various age-related diseases; however, their involvement in pulmonary fibrosis (PF) remains poorly understood. PF refers to a group of chronic interstitial lung diseases characterised by progressive scarring of the pulmonary parenchyma, primarily caused by aberrant tissue repair mechanisms. These changes lead to irreversible loss of lung function. Although the exact pathophysiological mechanism underlying PF has not yet been elucidated, recent studies have indicated that ECs may play a pivotal role in PF. This review outlines the involvement of pulmonary vascular ECs in PF, focusing on the regulation of vascular remodelling and endothelial barrier integrity and on the maintenance of angiogenesis through EC-specific markers, such as vascular endothelial growth factor. This review also explores processes such as endothelial-to-mesenchymal transition, immune cell interactions, anti-EC antibody reactions, metabolic dysregulation, and cellular senescence. By elucidating recent advancements in understanding the role of ECs in PF and examining drugs targeting ECs for the treatment of PF, this study provides novel insights into the pathological mechanisms of PF and the development of endothelium-based therapeutic agents.

Impaired ketogenesis in Leydig Cells drives testicular aging

Testicular aging commonly leads to testosterone deficiency and impaired spermatogenesis, yet the underlying mechanisms remain elusive. Here, we show that Leydig cells are particularly vulnerable to aging processes in testis. Single-cell RNA sequencing identifies the expression of Hmgcs2, the gene encoding rate-limiting enzyme of ketogenesis, decreases significantly in Leydig cells from aged mice. Additionally, the concentrations of ketone bodies β-hydroxybutyric acid and acetoacetic acid in young testes are substantially higher than that in serum, but significantly diminish in aged testes. Silencing of Hmgcs2 in young Leydig cells drives cell senescence and accelerated testicular aging. Mechanistically, β-hydroxybutyric acid upregulates the expression of Foxo3a by facilitating histone acetylation, thereby mitigating Leydig cells senescence and promoting testosterone production. Consistently, enhanced ketogenesis by genetic manipulation or oral β-hydroxybutyric acid supplementation alleviates Leydig cells senescence and ameliorates testicular aging in aged mice. These findings highlight defective ketogenesis as a pivotal factor in testicular aging, suggesting potential therapeutic avenues for addressing age-related testicular dysfunction.

Regulation of cellular senescence in tumor progression and therapeutic targeting: mechanisms and pathways

Cellular senescence, a stable state of cell cycle arrest induced by various stressors or genomic damage, is recognized as a hallmark of cancer. It exerts a context-dependent dual role in cancer initiation and progression, functioning as a tumor suppressor and promoter. The complexity of senescence in cancer arises from its mechanistic diversity, potential reversibility, and heterogeneity. A key mediator of these effects is the senescence-associated secretory phenotype (SASP), a repertoire of bioactive molecules that influence tumor microenvironment (TME) remodeling, modulate cancer cell behavior, and contribute to therapeutic resistance. Given its intricate role in cancer biology, senescence presents both challenges and opportunities for therapeutic intervention. Strategies targeting senescence pathways, including senescence-inducing therapies and senolytic approaches, offer promising avenues for cancer treatment. This review provides a comprehensive analysis of the regulatory mechanisms governing cellular senescence in tumors. We also discuss emerging strategies to modulate senescence, highlighting novel therapeutic opportunities. A deeper understanding of these processes is essential for developing precision therapies and improving clinical outcomes.

Treating Metabolic Dysregulation and Senescence by Caloric Restriction: Killing Two Birds with One Stone?

Cellular senescence is a state of permanent cell cycle arrest accompanied by metabolic activity and characteristic phenotypic changes. This process is crucial for developing age-related diseases, where excessive calorie intake accelerates metabolic dysfunction and aging. Overnutrition disturbs key metabolic pathways, including insulin/insulin-like growth factor signaling (IIS), the mammalian target of rapamycin (mTOR), and AMP-activated protein kinase. The dysregulation of these pathways contributes to insulin resistance, impaired autophagy, exacerbated oxidative stress, and mitochondrial dysfunction, further enhancing cellular senescence and systemic metabolic derangements. On the other hand, dysfunctional endothelial cells and adipocytes contribute to systemic inflammation, reduced nitric oxide production, and altered lipid metabolism. Numerous factors, including extracellular vesicles, mediate pathological communication between the vascular system and adipose tissue, amplifying metabolic imbalances. Meanwhile, caloric restriction (CR) emerges as a potent intervention to counteract overnutrition effects, improve mitochondrial function, reduce oxidative stress, and restore metabolic balance. CR modulates pathways such as IIS, mTOR, and sirtuins, enhancing glucose and lipid metabolism, reducing inflammation, and promoting autophagy. CR can extend the health span and mitigate age-related diseases by delaying cellular senescence and improving healthy endothelial-adipocyte interactions. This review highlights the crosstalk between endothelial cells and adipocytes, emphasizing CR potential in counteracting overnutrition-induced senescence and restoring vascular homeostasis.

Linarin Identified as a Bioactive Compound of Lycii Cortex Ameliorates Insulin Resistance and Inflammation Through the c-FOS/ARG2 Signaling Axis

Insulin resistance (IR) is a central pathophysiological process underlying numerous chronic metabolic disorders, including type 2 diabetes and obesity. Lycii Cortex, a widely used traditional Chinese herb, has demonstrated potential benefits in preventing and managing diabetes and IR. Whereas, the specific bioactive compounds responsible for these protective effects and their underlying mechanisms of action remain elusive. This study aimed to identify the bioactive components within Lycii Cortex that contribute to its anti-diabetic effects and to elucidate the molecular mechanisms underlying its beneficial actions on insulin resistance. Network pharmacology and molecular docking analyses were employed to identify the potential active compounds in Lycii Cortex and their corresponding target proteins. An in vitro model of IR was established using palmitic acid (PA)-treated HepG2 cells. Cell viability was assessed using the CCK-8 assay, while glucose uptake was evaluated by 2-NBDG staining and extracellular glucose measurement. To validate the in vitro findings, an in vivo model of obesity-induced IR was established using high-fat diet (HFD)-fed mice. The network pharmacology analysis preliminarily identified 13 candidate chemicals and 10 hub LyC and IR-related genes (LIRRGs). Molecular docking analysis demonstrates that Linarin as the potential active component exhibits the greatest potential to target c-FOS for preventing obesity-induced IR. Enrichment analysis suggested that Linarin-targeted pathways are correlated with inflammation. In vitro experimental validation demonstrated that Linarin was capable of protecting against PA-induced IR in HepG2 cells evidenced by improving glucose uptake ability and reducing extracellular glucose content. Additionally, we found that Linarin ablated PA-induced increase in the expression of c-FOS and inflammatory cytokines. Furthermore, in PA-treated cells, silencing c-FOS markedly improved glucose consumption, and reduced inflammation and Arginase 2 (ARG2) expression. Similarly, as exposure to PA, silencing ARG2 also ameliorated glucose uptake and inflammation, while not affecting c-FOS expression. In vivo experiments further showed that Linarin administration remarkably improved glucose tolerance and insulin sensitivity, and reduced the fat mass and body weight in HFD-induced obese mice. In this study, Linarin has been identified as the bioactive compound of Lycii Cortex to ameliorate obesity-related IR and inflammation through the c-FOS/ARG2 signaling cascade. These findings underscore the therapeutic potential of Linarin and provide valuable insights into developing novel intervention strategies for type 2 diabetes therapy.

Role of RNA-binding Proteins in Regulating Cell Adhesion and Progression of the Atherosclerotic Plaque and Plaque Erosion

PURPOSE OF REVIEW

RNA-binding proteins (RBPs) have emerged as crucial regulators of post-transcriptional processes, influencing the fate of RNA. This review delves into the biological functions of RBPs and their role in alternative splicing concerning atherosclerosis (AS), highlighting their participation in essential cellular processes. Our goal is to offer new insights for cardiovascular disease research and treatment.

RECENT FINDING

Dysregulation of RBPs is associated with various human diseases, including autoimmune and neurological disorders. The role of RBPs in the pathogenesis of AS is progressively being elucidated, as they influence plaque formation and disease progression by regulating cell function and gene expression. RBPs play intricate biological roles in regulating pre-mRNA, including editing, splicing, stability and translation. Alternative splicing has been demonstrated to enhance biological complexity and diversity. Our findings indicate that alternative splicing is extensively involved in the pathogenesis of AS. The dysregulated expression of specific RBPs in AS is linked to the production of adhesion molecules and vascular endothelium damage. Further research on RBPs could pave the way for the development of novel therapeutic targets.

Genome-Wide and Exome-Wide Association Study Identifies Genetic Underpinning of Comorbidity between Myocardial Infarction and Severe Mental Disorders

BACKGROUND

Myocardial Infarction (MI) and severe mental disorders (SMDs) are two types of highly prevalent and complex disorders and seem to have a relatively high possibility of mortality. However, the contributions of common and rare genetic variants to their comorbidity arestill unclear.

METHODS

We conducted a combined genome-wide association study (GWAS) and exome-wide association study (EWAS) approach.

RESULTS

Using gene-based and gene-set association analyses based on the results of GWAS, we found the common genetic underpinnings of nine genes (GIGYF2, KCNJ13, PCCB, STAG1, HLA-C, HLA-B, FURIN, FES, and SMG6) and nine pathways significantly shared between MI and SMDs. Through Mendelian randomization analysis, we found that twenty-seven genes were potential causal genes for SMDs and MI. Based on the exome sequencing data of MI and SMDs patients from the UK Biobank, we found that MUC2 was exome-wide significant in the two diseases. The gene-set analyses of the exome-wide association study indicated that pathways related to insulin processing androgen catabolic process and angiotensin receptor binding may be involved in the comorbidity between SMDs and MI. We also found that six candidate genes were reported to interact with known therapeutic drugs based on the drug-gene interaction information in DGIdb.

CONCLUSIONS

Altogether, this study revealed the overlap of common and rare genetic underpinning between SMDs and MI and may provide useful insights for their mechanism study and therapeutic investigations.

RNA-binding protein GIGYF2 orchestrates hepatic insulin resistance through STAU1/PTEN-mediated disruption of the PI3K/AKT signaling cascade

BACKGROUND

Obesity is well-established as a significant contributor to the development of insulin resistance (IR) and diabetes, partially due to elevated plasma saturated free fatty acids like palmitic acid (PA). Grb10-interacting GYF Protein 2 (GIGYF2), an RNA-binding protein, is widely expressed in various tissues including the liver, and has been implicated in diabetes-induced cognitive impairment. Whereas, its role in obesity-related IR remains uninvestigated.

METHODS

In this study, we employed palmitic acid (PA) exposure to establish an in vitro IR model in the human liver cancer cell line HepG2 with high-dose chronic PA treatment. The cells were stained with fluorescent dye 2-NBDG to evaluate cell glucose uptake. The mRNA expression levels of genes were determined by real-time qRT-PCR (RT-qPCR). Western blotting was employed to examine the protein expression levels. The RNA immunoprecipitation (RIP) was used to investigate the binding between protein and mRNA. Lentivirus-mediated gene knockdown and overexpression were employed for gene manipulation. In mice, an IR model induced by a high-fat diet (HFD) was established to validate the role and action mechanisms of GIGYF2 in the modulation of HFD-induced IR in vivo.

RESULTS

In hepatocytes, high levels of PA exposure strongly trigger the occurrence of hepatic IR evidenced by reduced glucose uptake and elevated extracellular glucose content, which is remarkably accompanied by up-regulation of GIGYF2. Silencing GIGYF2 ameliorated PA-induced IR and enhanced glucose uptake. Conversely, GIGYF2 overexpression promoted IR, PTEN upregulation, and AKT inactivation. Additionally, PA-induced hepatic IR caused a notable increase in STAU1, which was prevented by depleting GIGYF2. Notably, silencing STAU1 prevented GIGYF2-induced PTEN upregulation, PI3K/AKT pathway inactivation, and IR. STAU1 was found to stabilize PTEN mRNA by binding to its 3'UTR. In liver cells, tocopherol treatment inhibits GIGYF2 expression and mitigates PA-induced IR. In the in vivo mice model, GIGYF2 knockdown and tocopherol administration alleviate high-fat diet (HFD)-induced glucose intolerance and IR, along with the suppression of STAU1/PTEN and restoration of PI3K/AKT signaling.

CONCLUSIONS

Our study discloses that GIGYF2 mediates obesity-related IR by disrupting the PI3K/AKT signaling axis through the up-regulation of STAU1/PTEN. Targeting GIGYF2 may offer a potential strategy for treating obesity-related metabolic diseases, including type 2 diabetes.

SLC7A11-ROS/αKG-AMPK axis regulates liver inflammation through mitophagy and impairs liver fibrosis and NASH progression

The changes of inflammation and metabolism are two features in nonalcoholic steatohepatitis (NASH). However, how they interact to regulate NASH progression remains largely unknown. Our works have demonstrated the importance of solute carrier family 7 member 11 (SLC7A11) in inflammation and metabolism. Nevertheless, whether SLC7A11 regulates NASH progression through mediating inflammation and metabolism is unclear. In this study, we found that SLC7A11 expression was increased in liver samples from patients with NASH. Upregulated SLC7A11 level was also detected in two murine NASH models. Functional studies showed that SLC7A11 knockdown or knockout had augmented steatohepatitis with suppression of inflammatory markers in mice. However, overexpression of SLC7A11 dramatically alleviated diet-induced NASH pathogenesis. Mechanically, SLC7A11 decreased reactive oxygen species (ROS) level and promoted α-ketoglutarate (αKG)/prolyl hydroxylase (PHD) activity, which activated AMPK pathway. Furthermore, SLC7A11 impaired expression of NLRP3 inflammasome components through AMPK-mitophagy axis. IL-1β release through NLRP3 inflammasome recruited myeloid cells and promoted hepatic stellate cells (HSCs) activation, which contributed to the progression of liver injury and fibrosis. Anti-IL-1β and anakinra might attenuate the hepatic inflammatory response evoked by SLC7A11 knockdown. Moreover, the upregulation of SLC7A11 in NASH was contributed by lipid overload-induced JNK-c-Jun pathway. In conclusions, SLC7A11 acts as a protective factor in controlling the development of NASH. Upregulation of SLC7A11 is protective by regulating oxidation, αKG and energy metabolism, decreasing inflammation and fibrosis.