Hif-2α regulates lipid metabolism in alcoholic fatty liver disease through mitophagy

Current trends and landscape of drug resistance in renal cell carcinoma: a bibliometric analysis

INTRODUCTION

Renal cell carcinoma (RCC) is a common type of kidney cancer, and the prognosis for patients with advanced-stage disease remains poor. One major obstacle is the development of drug resistance, which severely limits the effectiveness of therapeutic interventions. This bibliometric study aims to provide a comprehensive overview of current research trends on drug resistance in RCC.

METHODS

This study examines publications on drug resistance in RCC from 2000 to 2023, sourced from the Web of Science Core Collection (WoSCC). Detailed analyses were conducted to identify research hotspots, academic collaborations, and emerging trends. CiteSpace, SCImago Graphica, and VOSviewer were utilized to conduct these analyses comprehensively.

RESULTS

This study analyzed a total of 2,804 publications from the WoSCC database. The number of annual publications showed a consistent upward trend, with an average annual growth rate of 8.12%. The United States had the highest number of publications, followed by China and Japan. The most productive institutions were the University of Texas System, Harvard University, and the National Institutes of Health (NIH). Alfred H. Schinkel emerged as the most prolific author, also having the highest H-index. The three most frequent research categories were oncology, pharmacology and pharmacy, and biochemistry and molecular biology. The evolution of research topics was assessed in 5-year intervals, revealing that recent themes such as ferroptosis and immunotherapy have gained increasing attention. Keyword analysis indicated a shift in research focus toward cell lipid metabolism, androgen receptor and specific molecular signatures.

CONCLUSION

This study offers the first comprehensive bibliometric analysis specifically focused on drug resistance in RCC. It identifies current research trends, highlights emerging hotspots, and provides insights into key contributors and ongoing challenges in the field. Our study provides a theoretical reference and guidance to guide future research efforts to address drug resistance in RCC more effectively.

Chronic intermittent hypoxia alleviates alcohol-related liver injury via downregulation of hepatic hypoxia-inducible factor-2α

Alcohol-related liver disease (ALD) is one of the leading causes of alcohol-related morbidity and mortality worldwide. Unfortunately, limited therapeutic options are currently available, due to the complex risk factors involved as well as the lack of information on the molecular mechanisms driving its progression. Interestingly, chronic, excessive alcohol intake has been reported to exacerbate the severity of obstructive sleep apnea (OSA), a respiratory disorder typically characterized by chronic intermittent hypoxia (CIH). However, this relationship between alcohol-enhanced OSA and ALD development/progression remains to be elucidated. As an approach to investigate this relationship, in vivo Gao-binge ALD and CIH mouse models were established. Alcohol-related liver injury, hepatic steatosis, inflammation, and oxidative stress were then assessed in these models. In addition, lipopolysaccharide (LPS) and ethanol-cotreated mouse normal hepatocyte cell line AML12 served as an in vitro model to investigate the mechanisms through which CIH affects ethanol-induced liver injury. CIH intervention ameliorated alcohol-related liver injury, reduced hepatic lipid accumulation and oxidative stress, and alleviated liver inflammation. Mechanistically, in the liver of these Gao-binge mice, CIH intervention inhibited alcohol-induced upregulation and activation of hypoxia-inducible factor 2α (HIF-2α), a protein which plays a key role in hepatic lipid metabolism and liver injury. Similar to these effects observed in response to CIH intervention, treatment of Gao-binge mice with the selective inhibitor of HIF-2α, PT2385, alleviated alcohol-related liver injury and steatosis while inhibiting oxidative stress and inflammation. Additional findings from our in vitro model revealed that CIH downregulated HIF-2α by promoting calpains protein expression, thereby reducing the accumulation of lipid droplets and decreasing reactiveoxygenspecies (ROS) production in AML12 cells co-challenged with LPS and ethanol. The above results provide important, new evidence that reconceptualizes the role of alcohol-enhanced OSA in ALD progression. Moreover, these findings can serve as the foundation for the development of HIF-2α inhibitors for use in the prevention and treatment of ALD.NEW & NOTEWORTHY Chronic intermittent hypoxia (CIH) intervention mitigated hepatic lipid accumulation and reduced hepatic injury, inflammation, and oxidative stress in alcohol-related liver disease (ALD) mice. CIH alleviates ALD and is likely linked to the downregulation of hypoxia-inducible factor 2α (HIF-2α) expression mediated by calpains. This study presents a new possibility for ALD treatment and lays a theoretical foundation for the clinical treatment of ALD.

Structure characteristics of a novel pectic polysaccharide from Fructus Corni and its protective effect on alcoholic fatty liver

Alcoholic fatty liver disease (AFLD) is characterized by the accumulation of hepatic lipid and has no effective treatment yet. Fructus Corni is a traditional Chinese medicinal herb, and its extractions have demonstrated hepatoprotective properties. We hypothesize that the polysaccharides in Fructus Corni might have therapeutic effects on AFLD. In this study, we isolated a novel homogeneous polysaccharide, APFC-2 (Mw= 63.0 kDa), from the Fructus Corni, and its structure was elucidated by monosaccharide composition, methylation analysis, partial acid hydrolysis, and NMR spectra. APFC-2 is a pectic polysaccharide characterized by a backbone of T-β-Galp-(1 → 6)-β-Galp-(1 → 3,6)-β-Galp-(1 → [4)-α-GalpA-OMe-(1 → 4)-α-GalpA-(1→]m → [2,4)-α-Rhap-(1 → 4)-α-GalpA-(1→]n, with branches comprising T-Araf-(1→, →3)-α-Araf-(1→, →3,5)-α-Araf-(1→, and →5)-α-Araf-(1→. In vivo experiments indicated that APFC-2 could significantly reduce hepatic steatosis, fasting triglyceride, and cholesterol levels in AFLD mice. Cell proliferation and Oil Red O staining results showed that APFC-2 concentration-dependently increased cell viability and significantly improved lipid metabolism in vitro. Mechanistically, APFC-2 markedly inhibited the formation of lipid both in vitro and in vivo through activating liver kinase B1 (LKB1) and then regulating adenosine 5'-monophosphate-activated protein kinase (AMPK)-SREBP-1 and AMPK-PPAR-α pathways. This research provides a theoretical basis for the potential application of Fructus Corni pectic polysaccharide as a specific activator of LKB1 for treating AFLD.

Potential Mechanisms and Effects of Dai Bai Jie Ethanol Extract in Preventing Acute Alcoholic Liver Injury

This study investigated the protective effect of Dai Bai Jie (DBJ) extract against acute alcoholic liver injury (AALI) and elucidated its potential mechanism. The total saponin level in the DBJ extracts was measured using vanillin-chloroform acid colorimetry. To observe the preventive and protective effects of DBJ on AML-12 cells in an ethanol environment, the effective components of DBJ were identified. An alcohol-induced AALI mouse model was used to evaluate the efficacy of DBJ against AALI. For this purpose, alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) levels were assessed, liver function indices and oxidative and inflammatory markers were determined, and histopathological examinations were performed. Mechanistic investigations were conducted using RT-qPCR assays and immunohistochemical analysis to determine the protective effects of DBJ. The samples (DBJ-1, DBJ-2, and DBJ-3) were obtained by extracting DBJ with water, 50% ethanol, and 95% ethanol, yielding total saponin contents of 5.35%, 6.64%, and 11.83%, respectively. DBJ-3 was isolated and purified, and its components were identified by Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS). DBJ-3 had the greatest effect on cell viability in an ethanol environment. Moreover, DBJ-3 reduced inflammatory infiltration, liver cell degeneration, and hemorrhage, while increasing ADH and ALDH levels in liver tissues. Additionally, DBJ-3 considerably decreased the serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), and triglyceride (TG) levels. DBJ-3 reduced malondialdehyde (MDA), reactive oxygen species (ROS), and inflammatory factors, such as tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), and interleukin 6 (IL-6), while increasing superoxide dismutase (SOD) and glutathione S-transferase (GST) activities. Furthermore, DBJ-3 significantly increased alcohol dehydrogenase 1b (ADH1B) and aldehyde dehydrogenase 2 (ALDH2) expression at the gene and protein levels within alcohol metabolism pathways and reduced the nuclear factor kappa-B (NF-κB) gene and protein levels. These findings suggest that DBJ-3 can prevent AALI by enhancing alcohol metabolism via the regulation of ADH1B and ALDH2 and the modulation of the NF-κB pathway to improve antioxidant and anti-inflammatory effects.

Hypoxia-inducible factor-2α promotes fibrosis in non-alcoholic fatty liver disease by enhancing glutamine catabolism and inhibiting yes-associated protein phosphorylation in hepatic stellate cells

Non-alcoholic fatty liver disease (NAFLD) has a high global prevalence and affects approximately one-third of adults, owing to high-fat dietary habits and a sedentary lifestyle. The role of hypoxia-inducible factor 2α (HIF-2α) in NAFLD progression remains unknown. This study aimed to investigate the effects of chronic hypoxia on NAFLD progression by examining the role of hypoxia-inducible factor 2α (HIF-2α) activation and that of hepatic stellate cell (HSC)-derived myofibroblasts through glutaminolysis. We hypothesised that hypoxia exacerbates NAFLD by promoting HIF-2α upregulation and inhibiting phosphorylated yes-associated protein (YAP), and that increasing YAP expression enhances HSC-derived myofibroblasts. We studied patients with NAFLD living at high altitudes, as well as animal models and cultured cells. The results revealed significant increases in HSC-derived myofibroblasts and collagen accumulation caused by HIF-2α and YAP upregulation, both in patients and in a mouse model for hypoxia and NAFLD. HIF-2α and HIF-2α-dependent YAP downregulation reduced HSC activation and myofibroblast levels in persistent chronic hypoxia. Furthermore, hypoxia-induced HIF-2α upregulation promoted YAP and inhibited YAP phosphorylation, leading to glutaminase 1 (GLS1), SLC38A1, α-SMA, and Collagen-1 overexpression. Additionally, hypoxia restored mitochondrial adenosine triphosphate production and reactive oxygen species (ROS) overproduction. Thus, chronic hypoxia-induced HIF-2α activation enhances fibrosis and NAFLD progression by restoring mitochondrial ROS production and glutaminase-1-induced glutaminolysis, which is mediated through the inhibition of YAP phosphorylation and increased YAP nuclear translocation. In summary, HIF-2α plays a pivotal role in NAFLD progression during chronic hypoxia.

Salvianolic acid A attenuates arsenic-induced ferroptosis and kidney injury via HIF-2α/DUOX1/GPX4 and iron homeostasis

Arsenic (As) is a prevalent pollutant in the environment and causes a high frequency of kidney disease in areas of high arsenic contamination, but its pathogenic mechanisms have yet to be completely clarified. Ferroptosis is a new form of cell death mainly dependent on lipid peroxidation and iron accumulation. Several reports have suggested that ferroptosis is operative in a spectrum of diseases caused by arsenic exposure, including in the lungs, pancreas, and testis. However, the mechanism and exact role of ferroptosis in arsenic-induced kidney injury is not known. Firstly, by constructing in vivo and in vitro arsenic exposure models, we confirmed the occurrence of ferroptosis based on the identification of the ability of NaASO2 to cause kidney injury. In addition, we found that arsenic exposure could upregulate DUOX1 expression in kidney and HK-2 cells, and after knocking down DUOX1 using siRNA was able to significantly upregulate GPX4 expression and attenuate ferroptosis. Subsequently using bioinformatics, we identified and proved the involvement of HIF-2α in the course of ferroptosis, and further confirmed by dual luciferase assay that HIF-2α promotes DUOX1 transcription to increase its expression. Finally, intervention with the natural ingredient SAA significantly attenuated arsenic-induced ferroptosis and kidney injury. These results showed that arsenic could cause ferroptosis and kidney injury by affecting HIF-2α/DUOX1/GPX4 and iron homeostasis and that SAA was an effective intervention component. This study not only discovered the molecular mechanism of sodium arsenite-induced kidney injury but also explored an active ingredient with intervention potential, providing a scientific basis for the prevention and treatment of sodium arsenite-induced kidney injury.

FBXL5 promotes lipid accumulation in alcoholic fatty liver disease by promoting the ubiquitination and degradation of TFEB

BACKGROUND

Alcoholic fatty liver disease (AFLD) is characterized by abnormal lipid droplet accumulation in liver. Epigenetic regulation plays an important role in the pathogenesis of AFLD. Comprehensive bioinformatics analysis revealed that an E3 ubiquitin ligase, F-box and leucine-rich repeats protein 5 (FBXL5), was significantly upregulated in AFLD mice.

METHODS

The mouse model of AFLD was established by feeding Lieber-DeCarli liquid diet containing ethanol. An in vitro model of AFLD was established by treating HepG2 cells with ethanol (EtOH). The FBXL5 expression was assessed by quantitative real-time PCR (qRT-PCR) and western blotting assays. The levels of triglyceride (TG), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lipid accumulation were analyzed by enzyme-linked immunosorbent assay (ELISA) and Nile red staining.

RESULTS

The FBXL5 expression was markedly up-regulated in in vivo and in vitro models of AFLD compared with controls. Functionally, FBXL5 knockdown alleviated lipid accumulation in EtOH-treated HepG2 cells. Mechanistically, FBXL5 directly interacted with transcription factor EB (TFEB) and accelerated its ubiquitination-mediated degradation. TFEB knockdown reversed the effect of FBXL5 inhibition on decreasing EtOH-induced lipid accumulation.

CONCLUSION

Our data suggest that FBXL5 promotes lipid accumulation in AFLD by promoting the ubiquitination and degradation of TFEB.