Hepatocyte Adenosine Kinase Promotes Excessive Fat Deposition and Liver Inflammation

Adenosine kinase inhibits β-cell proliferation by upregulating DNA methyltransferase 3A expression

AIM

To investigate the effects of adenosine kinase (ADK), a key enzyme in determining intracellular adenosine levels, on β cells, and their underlying mechanism.

METHODS

Genetic animal models and transgenic immortalized cells were applied to study the effect of ADK on islet beta-cell proliferation and function. The beta-cell mass and response to glucose were measured in vivo using mice with beta-cell-specific ADK overexpression, and in vitro using ADK-overexpressed immortalized beta-cell.

RESULTS

The expression of ADK in human islets at high abundance, especially in β cells, was decreased during the process of β-cell proliferation. Additionally, a transgenic mouse model (ADKtg/tg /Mip-Cre) was generated wherein the mouse Insulin1 gene promoter specifically overexpressed ADK in pancreatic β cells. The ADKtg/tg /Mip-Cre model exhibited impaired glucose tolerance, decreased fasting plasma insulin, loss of β-cell mass, and inhibited β-cell proliferation. Proteomic analysis revealed that ADK overexpression inhibited the expression of several proteins that promote cell proliferation and insulin secretion. Upregulating ADK in the β-cell line inhibited the expression of β-cell related regulatory molecules, including FoxO1, Appl1, Pxn, Pdx-1, Creb and Slc16a3. Subsequent in vitro experiments indicated that the inhibition of β-cell proliferation and the decreased expression of Pdx-1, Creb and Slc16a3 were rescued by DNA methyltransferase 3A (DNMT3A) knockdown in β cells.

CONCLUSION

In this study, we found that the overexpression of ADK decreased the expression of several genes that regulate β cells, resulting in the inhibition of β-cell proliferation and dysfunction by upregulating the expression of DNMT3A.

Echinops Asteraceae extract guards against malathion-induced liver damage via minimizing oxidative stress, inflammation, and apoptosis

Malathion (MAL) is one of the highly toxic organophosphorus (OP) compounds that induces hepatotoxicity. Echinops. ritro leaves extract (ERLE) is traditionally used in the treatment of bacterial/fungal infections. This study's goal was to investigate the potential of extracts from ERLE against hepatotoxicity induced by MAL in male albino rats. Four equal groups of forty mature male albino rats were created: The rats in the first group used as a control. The second group of rats received ERLE orally. The third group received MAL. ERLE and MAL were administered to the fourth group of rats. Six-week treatment groups were conducted. Using lipid peroxidation indicators [malondialdehyde (MDA), alanine aminotransferase (ALT), aspartate aminotransferase (AST)], oxidative stress markers [catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx)], apoptotic markers [Bcl-2 & caspase-3] and tumor necrosis factor alpha (TNF-α). Rats treated with MAL underwent a significant increase on MDA, ALT, AST, caspase-3 and TNF-α marker with a significant decrease in antioxidant markers [CAT, SOD, GPx] and Bcl-2. Histologically, MAL-treated group's liver sections displayed damaged hepatocytes with collapsed portions, pyknotic nuclei, vacuolated cytoplasm, and congested central veins. Ultra structurally, rat livers treated with MAL showed dilated cisternae of endoplasmic reticulum, swollen mitochondria with disrupted cristae, nuclei with disrupted chromatin content, multiple lysosomes, multiple vacuolations and a disrupted blood sinusoid. With rats treated with ERLE, these alterations were essentially non-existent. It is possible to conclude that ERLE protects against MAL hepatotoxicity, and that this protection is related, at least in part, to its antioxidant activities.

The lack of PPARα exacerbated the progression of non-alcoholic steatohepatitis in mice with spleen deficiency syndrome by triggering an inflammatory response

Background

In addition to abnormal liver inflammation, the main symptoms of non-alcoholic steatohepatitis (NASH) are often accompanied by gastrointestinal digestive dysfunction, consistent with the concept of spleen deficiency (SD) in traditional Chinese medicine. As an important metabolic sensor, whether peroxisome proliferator-activated receptor alpha (PPARα) participates in regulating the occurrence and development of NASH with SD (NASH-SD) remains to be explored.

Methods

Clinical liver samples were collected for RNA-seq analysis. C57BL/6J mice induced by folium sennae (SE) were used as an SD model. qPCR analysis was conducted to evaluate the inflammation and metabolic levels of mice. PPARα knockout mice (PPARαko) were subjected to SE and methionine-choline-deficient (MCD) diet to establish the NASH-SD model. The phenotype of NASH and the inflammatory indicators were measured using histopathologic analysis and qPCR as well.

Results

The abnormal expression of PPARα signaling, coupled with metabolism and inflammation, was found in the results of RNA-seq analysis from clinical samples. SD mice showed a more severe inflammatory response in the liver evidenced by the increases in macrophage biomarkers, inflammatory factors, and fibrotic indicators in the liver. qPCR results also showed differences in PPARα between SD mice and control mice. In PPARαko mice, further evidence was found that the lack of PPARα exacerbated the inflammatory response phenotype as well as the lipid metabolism disorder in NASH-SD mice.

Conclusion

The abnormal NR signaling accelerated the vicious cycle between lipotoxicity and inflammatory response in NAFLD with SD. Our results provide new evidence for nuclear receptors as potential therapeutic targets for NAFLD with spleen deficiency.

Recent progress on the application of compound formulas of traditional Chinese medicine in clinical trials and basic research in vivo for chronic liver disease

ETHNOPHARMACOLOGICAL RELEVANCE

Chronic liver diseases mainly include chronic viral liver disease, metabolic liver disease, cholestatic liver disease (CLD), autoimmune liver disease, and liver fibrosis or cirrhosis. Notably, the compound formulas of traditional Chinese medicine (TCM) is effective for chronic liver diseases in clinical trials and basic research in vivo, which provide evidence of chronic liver disease treatment with integrated TCM and traditional Western medicine.

AIM OF THE REVIEW

This paper aims to provide a comprehensive review of the compound formulas of TCM for treating different chronic liver diseases to elucidate the composition, main curative effects, and mechanisms of these formulas and research methods.

MATERIALS AND METHODS

Different keywords related to chronic liver diseases and keywords related to the compound formulas of TCM were used to search the literature. PubMed, Scopus, Web of Science, and CNKI were searched to screen out original articles about the compound formulas of TCM related to the treatment of chronic liver diseases, mainly including clinical trials and basic in vivo research related to Chinese patent drugs, classic prescriptions, proven prescriptions, and hospital preparations. We excluded review articles, meta-analysis articles, in vitro experiments, articles about TCM monomers, articles about single-medicine extracts, and articles with incomplete or uncertain description of prescription composition. Plant names were checked with MPNS (http://mpns.kew.org).

RESULTS

In this review, the clinical efficacy and mechanism of compound formulas of TCM were summarized for the treatment of chronic viral hepatitis, nonalcoholic fatty liver disease, CLD, and liver fibrosis or cirrhosis developed from these diseases and other chronic liver diseases. For each clinical trial and basic research in vivo, this review provides a detailed record of the specific composition of the compound formulas of TCM, type of clinical research, modeling method of animal experiments, grouping methods, medication administration, main efficacy, and mechanisms.

CONCLUSION

The general development process of chronic liver disease can be summarized as chronic hepatitis, liver fibrosis or cirrhosis, and hepatocellular carcinoma. The compound formulas of TCM have some applications in these stages of chronic liver diseases. Owing to the continuous progress of medical technology, the benefits of the compound formulas of TCM in the treatment of chronic liver diseases are constantly changing and developing.

Direct degradation and stabilization of proteins: New horizons in treatment of nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is featured with excessive hepatic lipid accumulation and its global prevalence is soaring. Nonalcoholic steatohepatitis (NASH), the severe systemic inflammatory subtype of NAFLD, is tightly associated with metabolic comorbidities, and the hepatocytes manifest severe inflammation and ballooning. Currently the therapeutic options for treating NASH are limited. Potent small molecules specifically intervene with the signaling pathways that promote pathogenesis of NASH. Nevertheless they have obvious adverse effects and show long-term ineffectiveness in clinical trials. It poses the fundamental question to efficiently and safely inhibit the pathogenic processes. Targeted protein degradation (TPD) belongs to the direct degradation strategies and is a burgeoning strategy. It utilizes the small molecules to bind to the target proteins and recruit the endogenous proteasome, lysosome and autophagosome-mediated degradation machineries. They effectively and specifically degrade the target proteins. It has exhibited promising therapeutic effects in treatment of cancer, neurodegenerative diseases and other diseases in a catalytic manner at low doses. We critically discuss the principles of multiple direct degradation strategies, especially PROTAC and ATTEC. We extensively analyze their emerging application in degradation of excessive pathogenic proteins and lipid droplets, which promote the progression of NASH. Moreover, we discuss the opposite strategy that utilizes the small molecules to recruit deubiquinases to stabilize the NASH/MASH-suppressing proteins. Their advantages, limitations, as well as the solutions to address the limitations have been analyzed. In summary, the innovative direct degradation strategies provide new insights into design of next-generation therapeutics to combat NASH with optimal safety paradigm and efficiency.

Emerging applications of single-cell profiling in precision medicine of atherosclerosis

Atherosclerosis is a chronic, progressive, inflammatory disease that occurs in the arterial wall. Despite recent advancements in treatment aimed at improving efficacy and prolonging survival, atherosclerosis remains largely incurable. In this review, we discuss emerging single-cell sequencing techniques and their novel insights into atherosclerosis. We provide examples of single-cell profiling studies that reveal phenotypic characteristics of atherosclerosis plaques, blood, liver, and the intestinal tract. Additionally, we highlight the potential clinical applications of single-cell analysis and propose that combining this approach with other techniques can facilitate early diagnosis and treatment, leading to more accurate medical interventions.

Roles of immune dysregulation in MASLD

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease worldwide. Its occurrence and progression involve the process from simple hepatic steatosis to metabolic dysfunction associated steatohepatitis (MASH), which could develop into advanced liver fibrosis, cirrhosis, or hepatocellular carcinoma (HCC). Growing evidences support that the pathogenesis and progression of MASLD are closely related to immune system dysfunction. This review aims to summarize the association of MASLD with immune disorders and the prospect of using immunotherapy for MASLD.

15-deoxy-Δ12,14-prostaglandin J2 relieved acute liver injury by inhibiting macrophage migration inhibitory factor expression via PPARγ in hepatocyte

15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) exhibited potential to alleviate liver inflammation in chronic injury but was less studied in acute injury. Acute liver injury was associated with elevated macrophage migration inhibitory factor (MIF) levels in damaged hepatocytes. This study aimed to investigate the regulatory mechanism of hepatocyte-derived MIF by 15d-PGJ2 and its subsequent impact on acute liver injury. In vivo, mouse models were established by carbon tetrachloride (CCl4) intraperitoneal injection, with or without 15d-PGJ2 administration. 15d-PGJ2 treatment reduced the necrotic areas induced by CCl4. In the same mouse model constructed using enhanced green fluorescent protein (EGFP)-labeled bone marrow (BM) chimeric mice, 15d-PGJ2 reduced CCl4 induced BM-derived macrophage (BMM, EGFP+F4/80+) infiltration and inflammatory cytokine expression. Additionally, 15d-PGJ2 down-regulated liver and serum MIF levels; liver MIF expression was positively correlated with BMM percentage and inflammatory cytokine expression. In vitro, 15d-PGJ2 inhibited Mif expression in hepatocytes. In primary hepatocytes, reactive oxygen species inhibitor (NAC) showed no effect on MIF inhibition by 15d-PGJ2; PPARγ inhibitor (GW9662) abolished 15d-PGJ2 suppressed MIF expression and antagonists (troglitazone, ciglitazone) mimicked its function. In Pparg silenced AML12 cells, the suppression of MIF by 15d-PGJ2 was weakened; 15d-PGJ2 promoted PPARγ activation in AML 12 cells and primary hepatocytes. Furthermore, the conditioned medium of recombinant MIF- and lipopolysaccharide-treated AML12 respectively promoted BMM migration and inflammatory cytokine expression. Conditioned medium of 15d-PGJ2- or siMif-treated injured AML12 suppressed these effects. Collectively, 15d-PGJ2 activated PPARγ to suppress MIF expression in injured hepatocytes, reducing BMM infiltration and pro-inflammatory activation, ultimately alleviating acute liver injury.

Understanding natural selection in Holocene Europe using multi-locus genotype identity scans

Ancient DNA (aDNA) has been a revolutionary technology in understanding human history but has not been used extensively to study natural selection as large sample sizes to study allele frequency changes over time have thus far not been available. Here, we examined a time transect of 708 published samples over the past 7,000 years of European history using multi-locus genotype-based selection scans. As aDNA data is affected by high missingness, ascertainment bias, DNA damage, random allele calling, and is unphased, we first validated our selection scan, G 12 a n c i e n t , on simulated data resembling aDNA under a demographic model that captures broad features of the allele frequency spectrum of European genomes as well as positive controls that have been previously identified and functionally validated in modern European datasets on data from ancient individuals from time periods very close to the present time. We then applied our statistic to the aDNA time transect to detect and resolve the timing of natural selection occurring genome wide and found several candidates of selection across the different time periods that had not been picked up by selection scans using single SNP allele frequency approaches. In addition, enrichment analysis discovered multiple categories of complex traits that might be under adaptation across these periods. Our results demonstrate the utility of applying different types of selection scans to aDNA to uncover putative selection signals at loci in the ancient past that might have been masked in modern samples.

Mini review: STING activation during non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic diseases serving as a major threat to human health. While the pathogenesis of NAFLD is multi-factorial, inflammation is considered a critical factor driving the development and progression of NAFLD phenotype, including liver fibrosis. As an essential mediator of innate immunity, stimulator of interferon genes (STING) functions to promote anti-viral immunity. Accumulating evidence also indicates that STING functions to promote the proinflammatory activation of several types of liver cells, especially macrophages/Kupffer cells, in a manner independent of interferon production. Over the past several years, a significant body of literature has validated a detrimental role for STING in regulating the pathogenesis of hepatic steatosis and inflammation. In particular, the STING in macrophages/Kupffer cells has attracted much attention due to its importance in not only enhancing macrophage proinflammatory activation, but also generating macrophage-derived mediators to increase hepatocyte fat deposition and proinflammatory responses, and to activate hepatic stellate cell fibrogenic activation. Both intracellular and extracellular signals are participating in STING activation in macrophages, thereby critically contributing to NAFLD phenotype. This mini review summarizes recent advances on how STING is activated in macrophages in the context of NAFLD pathophysiology.