TXNIP/VDUP1 attenuates steatohepatitis via autophagy and fatty acid oxidation

TXNIP deficiency attenuates renal fibrosis by modulating mTORC1/TFEB-mediated autophagy in diabetic kidney disease

Thioredoxin-interacting protein (TXNIP) is an important regulatory protein for thioredoxin (TRX) that elicits the generation of reactive oxygen species (ROS) by inhibiting the redox function of TRX. Abundant evidence suggests that TXNIP is involved in the fibrotic process of diabetic kidney disease (DKD). However, the potential mechanism of TXNIP in DKD is not yet well understood. In this study, we found that TXNIP knockout suppressed renal fibrosis and activation of mammalian target of rapamycin complex 1 (mTORC1) and restored transcription factor EB (TFEB) and autophagy activation in diabetic kidneys. Simultaneously, TXNIP interference inhibited epithelial-to-mesenchymal transformation (EMT), collagen I and fibronectin expression, and mTORC1 activation, increased TFEB nuclear translocation, and promoted autophagy restoration in HK-2 cells exposed to high glucose (HG). Rapamycin, an inhibitor of mTORC1, increased TFEB nuclear translocation and autophagy in HK-2 cells under HG conditions. Moreover, the TFEB activators, curcumin analog C1 and trehalose, effectively restored HG-induced autophagy, and abrogated HG-induced EMT and collagen I and fibronectin expression in HK-2 cells. Taken together, these findings suggest that TXNIP deficiency ameliorates renal fibrosis by regulating mTORC1/TFEB-mediated autophagy in diabetic kidney diseases.

The absence of thioredoxin-interacting protein in alveolar cells exacerbates asthma during obesity

Obesity is associated with an increased incidence of asthma. However, the mechanisms underlying this association are not fully understood. In this study, we investigated the role of thioredoxin-interacting protein (TXNIP) in obesity-induced asthma. Asthma was induced by intranasal injection of a protease from Aspergillus oryzae in normal diet (ND)- or high fat diet (HFD)-fed mice to investigate the symptoms. We measured TXNIP expression in the lungs of patients with asthma and in ND or HFD asthmatic mice. To explore the role of TXNIP in asthma pathogenesis, we induced asthma in the same manner in alveolar type 2 cell-specific TXNIP deficient (TXNIPCre) mice. In addition, the expression levels of pro-inflammatory cytokines were compared based on TXNIP gene expression in A549 cells stimulated with recombinant human tumor necrosis factor alpha. Compared to ND-fed mice, HFD-fed mice had elevated levels of free fatty acids and adipokines, resulting in high reactive oxygen species levels and more severe asthma symptoms. TXNIP expression was increased in both, asthmatic patients and HFD asthmatic mice. However, in experiments using TXNIPCre mice, despite being TXNIP deficient, TXNIPCre mice exhibited exacerbated asthma symptoms. Consistent with this, in vitro studies showed highest expression levels of pro-inflammatory cytokines in TXNIP-silenced cells. Overall, our findings suggest that increased TXNIP levels in obesity-induced asthma is compensatory to protect against inflammatory responses.

Study on the susceptibility of bovine coronavirus to BALB/c mice

There are no other bovine coronavirus (BCoV) infection models except calves, which makes efficacy evaluation of vaccines and pathogenic mechanism research of BCoV inconvenient owing to their high value and inconvenient operation. This study aimed to establish a mouse model of BCoV infection. BCoV was used to infect 4-week-old male BALB/c mice and the optimal infection conditions were screened, including the following infection routes: gavage, intraperitoneal injection, and tail vein injection at doses of 1 × 108 TCID50, 2 × 108 TCID50 and 4 × 108 TCID50. Using the optimal infection conditions, BALB/c mice were infected with BCoV, and their body weight, blood routine, inflammatory factors, autopsy, virus distribution, and viral load were measured at 1, 3, 5, and 7 days after infection. The results showed that the optimal conditions for infecting BALB/c mice with BCoV HLJ-325 strain were continuous oral gavage for 3 days with a dose of 4 × 108 TCID50. On the 7th day after infection, there was significant extensive consolidation of the lungs and thinning of the colon wall. Significant inflammation was observed in various organs, especially in the colon and alveoli, where a large number of inflammatory cells infiltrate. Both BCoV Ag and nucleic acid are positive in visceral organs. The viral load in the colon and lungs was significantly higher than that in the other organs (p < 0.001). BCoV-infected mice showed a decreasing trend in body weight starting from day 5, and there was a significant difference compared to the control group on days 6 and 7 (p < 0.001). The total number of white blood cells and lymphocytes began to decrease and was significantly lower than that in the control group 24 h after infection (p < 0.001), and gradually returned to the control level. The cytokine TNF-α, IL-1β, and IL-6 showed an increasing trend, significantly higher than the control group on day 5 and 7 (p < 0.001). These results indicate that the BCoV HLJ-325 strain can infect BALB/c mice and cause inflammatory reactions and tissue lesions. The most significant effect was observed on the seventh day after infection with a dose of 4 × 108 TCID50 and three consecutive gavages. This study established, for the first time, a BALB/c mouse model of BCoV infection, providing a technical means for evaluating the immune efficacy of BCoV vaccines and studying their pathogenic mechanisms.

Morroniside delays the progression of non-alcoholic steatohepatitis by promoting AMPK-mediated lipophagy

BACKGROUND

Non-alcoholic steatohepatitis (NASH), the inflammatory subtype in the progression of non-alcoholic fatty liver disease, is becoming a serious burden threatening human health, but no approved medication is available to date. Mononoside is a natural active substance derived from Cornus officinalis and has been confirmed to have great potential in regulating lipid metabolism in our previous studies. However, its effect and mechanism to inhibit the progression of NASH remains unclear.

PURPOSE

Our work aimed to explore the action of mononoside in delaying the progression of NASH and its regulatory mechanisms from the perspective of regulating lipophagy.

METHODS AND RESULTS

Male C57BL/6 mice were fed with a high-fat and high-fructose diet for 16 weeks to establish a NASH mouse model. After 8 weeks of high-fat and high-fructose feeding, these mice were administrated with different doses of morroniside. H&E staining, ORO staining, Masson staining, RNA-seq, immunoblotting, and immunofluorescence were performed to determine the effects and molecular mechanisms of morroniside in delaying the progression of NASH. In this study, we found that morroniside is effective in attenuating hepatic lipid metabolism disorders and inflammatory response activation, thereby limiting the progression from simple fatty liver to NASH in high-fat and high-fructose diet-fed mice. Mechanistically, we identified AMPK signaling as the key molecular pathway for the positive efficacy of morroniside by transcriptome sequencing. Our results revealed that morroniside maintained hepatic lipid metabolism homeostasis and inhibited NLRP3 inflammasome activation by promoting AMPKα phosphorylation-mediated lipophagy and fatty acid oxidation. Consistent results were observed in palmitic acid-treated cell models. Of particular note, silencing AMPKα both in vivo and in vitro reversed morroniside-induced lipophagy flux enhancement and NLRP3 inflammasome inhibition, emphasizing the critical role of AMPKα activation in the effect of morroniside in inhibiting NASH progression.

CONCLUSION

In summary, the present study provides strong evidence for the first time that morroniside inhibits NASH progression by promoting AMPK-dependent lipophagy and inhibiting NLRP3 inflammasome activation, suggesting that morroniside is expected to be a potential molecular entity for the development of therapeutic drugs for NASH.

The double-edged effects of IL-6 in liver regeneration, aging, inflammation, and diseases

Interleukin-6 (IL-6) is a pleiotropic cytokine and exerts its complex biological functions mainly through three different signal modes, called cis-, trans-, and cluster signaling. When IL-6 binds to its membrane or soluble receptors, the co-receptor gp130 is activated to initiate downstream signaling and induce the expression of target genes. In the liver, IL-6 can perform its anti-inflammatory activities to promote hepatocyte reprogramming and liver regeneration. On the contrary, IL-6 also exerts the pro-inflammatory functions to induce liver aging, fibrosis, steatosis, and carcinogenesis. However, understanding the roles and underlying mechanisms of IL-6 in liver physiological and pathological processes is still an ongoing process. So far, therapeutic agents against IL‑6, IL‑6 receptor (IL‑6R), IL-6-sIL-6R complex, or IL-6 downstream signal transducers have been developed, and determined to be effective in the intervention of inflammatory diseases and cancers. In this review, we summarized and highlighted the understanding of the double-edged effects of IL-6 in liver homeostasis, aging, inflammation, and chronic diseases, for better shifting the "negative" functions of IL-6 to the "beneficial" actions, and further discussed the potential therapeutic effects of targeting IL-6 signaling in the clinics.

Lipid Nanoparticle-Mediated Delivery of CRISPR-Cas9 Against Rubicon Ameliorates NAFLD by Modulating CD36 Along with Glycerophospholipid Metabolism

Non-alcoholic fatty liver disease (NAFLD) is a prominent cause of various chronic metabolic hepatic diseases with limited therapeutics. Rubicon, an essential regulator in lysosomal degradation, is reported to exacerbate hepatic steatosis in NAFLD mice and patients, indicating its probability of being a therapeutic target for NAFLD treatment. In this study, the therapeutic potential of Rubicon blockage is investigated. Lipid nanoparticles carrying Rubicon-specific CRISPR-Cas9 components exhibited liver accumulation, cell internalization, and Rubicon knockdown. A single administration of the nanoparticles results in attenuated lipid deposition and hepatic steatosis, with lower circulating lipid levels and decreased adipocyte size in NAFLD mice. Furthermore, the increase of phosphatidylcholine and phosphatidylethanolamine levels can be observed in the NAFLD mice livers after Rubicon silencing, along with regulatory effects on metabolism-related genes such as CD36, Gpcpd1, Chka, and Lpin2. The results indicate that knockdown of Rubicon improves glycerophospholipid metabolism and thereby ameliorates the NAFLD progression, which provides a potential strategy for NAFLD therapy via the restoration of Rubicon.

Long-chain fatty acids - The turning point between 'mild' and 'severe' acute pancreatitis

Acute pancreatitis (AP) is an inflammatory disease characterized by localized pancreatic injury and a systemic inflammatory response. Fatty acids (FAs), produced during the breakdown of triglycerides (TGs) in blood and peripancreatic fat, escalate local pancreatic inflammation to a systemic level by damaging pancreatic acinar cells (PACs) and triggering M1 macrophage polarization. This paper provides a comprehensive analysis of lipases' roles in the onset and progression of AP, as well as the effects of long-chain fatty acids (LCFAs) on the function of pancreatic acinar cells (PACs). Abnormalities in the function of PACs include Ca2+ overload, premature trypsinogen activation, protein kinase C (PKC) expression, endoplasmic reticulum (ER) stress, and mitochondrial and autophagic dysfunction. The study highlights the contribution of long-chain saturated fatty acids (LC-SFAs), especially palmitic acid (PA), to M1 macrophage polarization through the activation of the NLRP3 inflammasome and the NF-κB pathway. Furthermore, we investigated lipid lowering therapy for AP. This review establishes a theoretical foundation for pro-inflammatory mechanisms associated with FAs in AP and facilitating drug development.

Cross-species metabolomic profiling reveals phosphocholine-mediated liver protection from cold and ischemia/reperfusion

Cold and ischemia/reperfusion (IR)-associated injuries are seemingly inevitable during liver transplantation and hepatectomy. Because Syrian hamsters demonstrate intrinsic tolerance to transplantation-like stimuli, cross-species comparative metabolomic analyses were conducted with hamster, rat, and donor liver samples to seek hepatic cold and IR-adaptive mechanisms. Lower hepatic phosphocholine contents were found in recipients with early graft-dysfunction and with virus-caused cirrhosis or high model for end-stage liver disease scores (≥30). Choline/phosphocholine deficiency in cultured human THLE-2 hepatocytes and animal models weakened hepatocellular cold tolerance and recovery of glutathione and ATP production, which was rescued by phosphocholine supplements. Among the biological processes impacted by choline/phosphocholine deficiency, 3 lipid-related metabolic processes were downregulated, whereas phosphocholine elevated the expression of genes in methylation processes. Consistently, in THLE-2, phosphocholine enhanced the overall RNA m6A methylation, among which the transcript stability of fatty acid desaturase 6 (FADS6) was improved. FADS6 functioned as a key phosphocholine effector in the production of polyunsaturated fatty acids, which may facilitate the hepatocellular recovery of energy and redox homeostasis. Thus, our study reveals the choline-phosphocholine metabolism and its downstream FADS6 functions in hepatic adaptation to cold and IR, which may inspire new strategies to monitor donor liver quality and improve recipient recovery from the liver transplantation process.

Si-Wu-Tang alleviates metabolic dysfunction-associated fatty liver disease by inhibiting ACSL4-mediated arachidonic acid metabolism and ferroptosis in MCD diet-fed mice

BACKGROUND

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a prevalent chronic liver disease worldwide. Si-Wu-Tang (SWT), a traditional Chinese medicine decoction has shown therapeutic effects on various liver diseases. However, the hepatoprotective effects and underlying mechanism of SWT on MAFLD remain unclear.

METHODS

First, a methionine-choline-deficient (MCD) diet-fed mice model was used and lipidomic analysis and transcriptomic analysis were performed. The contents of total iron ions, ferrous ions, and lipid peroxidation were detected and Prussian blue staining was performed to confirm the protective effects of SWT against ferroptosis. Finally, chemical characterization and network pharmacological analysis were employed to identify the potential active ingredients.

RESULTS

Serological and hepatic histopathological findings indicated SWT's discernible therapeutic impact on MCD diet-induced MAFLD. Lipidomic analysis revealed that SWT improved intrahepatic lipid accumulation by inhibiting TG synthesis and promoting TG transport. Transcriptomic analysis suggested that SWT ameliorated abnormal FA metabolism by inhibiting FA synthesis and promoting FA β-oxidation. Then, ferroptosis phenotype experiments revealed that SWT could effectively impede hepatocyte ferroptosis, which was induced by long-chain acyl-CoA synthetase 4 (ACSL4)-mediated esterification of arachidonic acid (AA). Finally, chemical characterization and network pharmacological analysis identified that paeoniflorin and other active ingredients might be responsible for the regulative effects against ferroptosis and MAFLD.

CONCLUSION

In conclusion, our study revealed the intricate mechanism through which SWT improved MCD diet-induced MAFLD by targeting FA metabolism and ferroptosis in hepatocytes, thus offering a novel therapeutic approach for the treatment of MAFLD and its complications.

Choline suppresses hepatocellular carcinoma progression by attenuating AMPK/mTOR-mediated autophagy via choline transporter SLC5A7 activation

Background

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-associated death. Emerging evidence suggests that autophagy plays a critical role in HCC tumorigenesis, metastasis, and prognosis. Choline is an essential nutrient related to prolonged survival and reduced risk of HCC. However, it remains unclear whether this phenomenon is mediated by autophagy.

Methods

Two HCC cell lines (HUH-7 and Hep3B) were used in the present study. Cell growth was evaluated by cell counting kit 8 (CCK-8), colony formation, and in vivo mouse xenografts assays. Cell motility was calculated by wound healing and transwell assays. Autophagosomes were measured by transmission electron microscope (TEM), and autophagy flux was detected by mRFP-GFP-labeled LC3 protein. The mRNA level of genes was measured by quantitative real-time polymerase chain reaction (qRT-PCR). The protein levels were detected by Western blotting (WB).

Results

We found that choline inhibited the proliferation, migration, and invasion of HCC cells by downregulating autophagy in vitro and in vivo. Upregulated expression of the solute carrier family 5 member 7 (SLC5A7), a specific choline transporter, correlated with better HCC prognosis. We further discovered that choline could promote SLC5A7 expression, upregulate cytoplasm p53 expression to impair the AMPK/mTOR pathway, and attenuate autophagy. Finally, we found that choline acted synergistically with sorafenib to attenuate HCC development in vitro and in vivo.

Conclusions

Our findings provide novel insights into choline-mediated autophagy in HCC, providing the foothold for its future application in HCC treatment.

Punicalagin Ameliorates Diabetic Liver Injury by Inhibiting Pyroptosis and Promoting Autophagy via Modulation of the FoxO1/TXNIP Signaling Pathway

Diabetic liver injury (DLI) is one of the complications of diabetes mellitus, which seriously jeopardizes human health. Punicalagin (PU), a polyphenolic compound mainly found in pomegranate peel, has been shown to ameliorate metabolic diseases such as DLI, and the mechanism needs to be further explored. In this study, a HFD/STZ-induced diabetic mouse model is established to investigate the effect and mechanism of PU on DLI. The results show that PU intervention significantly improves liver histology and serum biochemical abnormalities in diabetic mice, significantly inhibits the expression of pyroptosis-related proteins such as NLRP3, Caspase1, IL-1β, and GSDMD in the liver of diabetic mice, and up-regulated the expression of autophagy-related proteins. Meanwhile, PU treatment significantly increases FoxO1 protein expression and inhibits TXNIP protein expression in the liver of diabetic mice. The above results are further verified in the HepG2 cell injury model induced by high glucose. AS1842856 is a FoxO1 specific inhibitor. The intervention of AS1842856 combined with PU reverses the regulatory effects of PU on pyroptosis and autophagy in HepG2 cells. In conclusion, this study demonstrates that PU may inhibit pyroptosis and upregulate autophagy by regulating FoxO1/TXNIP signaling, thereby alleviating DLI.

Nuclear miR-204-3p mitigates metabolic dysfunction-associated steatotic liver disease in mice

BACKGROUND & AIMS

Accumulating evidence has indicated the presence of mature microRNAs (miR) in the nucleus, but their effects on steatohepatitis remain elusive. We have previously demonstrated that the intranuclear miR-204-3p in macrophages protects against atherosclerosis, which shares multiple risk factors with metabolic dysfunction-associated steatotic liver disease (MASLD). Herein, we aimed to explore the functional significance of miR-204-3p in steatohepatitis.

METHODS

miR-204-3p levels and subcellular localization were assessed in the livers and peripheral blood mononuclear cells of patients with MASLD. Wild-type mice fed high-fat or methionine- and choline-deficient diets were injected with an adeno-associated virus system containing miR-204-3p to determine the effect of miR-204-3p on steatohepatitis. Co-culture systems were applied to investigate the crosstalk between macrophages and hepatocytes or hepatic stellate cells (HSCs). Multiple high-throughput epigenomic sequencings were performed to explore miR-204-3p targets.

RESULTS

miR-204-3p expression decreased in livers and macrophages in mice and patients with fatty liver. In patients with MASLD, miR-204-3p levels in peripheral blood mononuclear cells were inversely related to the severity of hepatic inflammation and damage. Macrophage-specific miR-204-3p overexpression reduced steatohepatitis in high-fat or methionine- and choline-deficient diet-fed mice. miR-204-3p-overexpressing macrophages inhibited TLR4/JNK signaling and pro-inflammatory cytokine release, thereby limiting fat deposition and inflammation in hepatocytes and fibrogenic activation in HSCs. Epigenomic profiling identified miR-204-3p as a specific regulator of ULK1 expression. ULK1 transcription and VPS34 complex activation by intranuclear miR-204-3p improved autophagic flux, promoting the anti-inflammatory effects of miR-204-3p in macrophages.

CONCLUSIONS

miR-204-3p inhibits macrophage inflammation, coordinating macrophage actions on hepatocytes and HSCs to ameliorate steatohepatitis. Macrophage miR-204-3p may be a therapeutic target for MASLD.

IMPACT AND IMPLICATIONS

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a chronic inflammatory disease ranging from simple steatosis to steatohepatitis. However, the molecular mechanisms underlying the progression of MASLD remain incompletely understood. Here, we demonstrate that miR-204-3p levels in circulating peripheral blood mononuclear cells are negatively correlated with disease severity in patients with MASLD. Nuclear miR-204-3p activates ULK1 transcription and improves autophagic flux, limiting macrophage activation and hepatic steatosis. Our study provides a novel understanding of the mechanism of macrophage autophagy and inflammation in steatohepatitis and suggests that miR-204-3p may act as a potential therapeutic target for MASLD.

Inflammation-mediated metabolic regulation in adipose tissue

Chronic inflammation of adipose tissue is a prominent characteristic of many metabolic diseases. Lipid metabolism in adipose tissue is consistently dysregulated during inflammation, which is characterized by substantial infiltration by proinflammatory cells and high cytokine concentrations. Adipose tissue inflammation is caused by a variety of endogenous factors, such as mitochondrial dysfunction, reactive oxygen species (ROS) production, endoplasmic reticulum (ER) stress, cellular senescence, ceramides biosynthesis and mediators of lipopolysaccharides (LPS) signaling. Additionally, the gut microbiota also plays a crucial role in regulating adipose tissue inflammation. Essentially, adipose tissue inflammation arises from an imbalance in adipocyte metabolism and the regulation of immune cells. Specific inflammatory signals, including nuclear factor-κB (NF-κB) signaling, inflammasome signaling and inflammation-mediated autophagy, have been shown to be involved in the metabolic regulation. The pathogenesis of metabolic diseases characterized by chronic inflammation (obesity, insulin resistance, atherosclerosis and nonalcoholic fatty liver disease [NAFLD]) and recent research regarding potential therapeutic targets for these conditions are also discussed in this review.

Pin1 Exacerbates Non-Alcoholic Fatty Liver Disease by Enhancing Its Activity through Binding to ACC1

Non-alcoholic fatty liver disease (NAFLD) is a clinicopathological syndrome characterized by diffuse hepatocellular steatosis due to fatty deposits in hepatocytes, excluding alcohol and other known liver injury factors. However, there are no specific drugs for the clinical treatment of NAFLD. Therefore, research on the pathogenesis of NAFLD at the cellular and molecular levels is a promising approach to finding therapeutic targets and developing targeted drugs for NAFLD. Pin1 is highly expressed during adipogenesis and contributes to adipose differentiation, but its specific mechanism of action in NAFLD is unclear. In this study, we investigated the role of Pin1 in promoting the development of NAFLD and its potential mechanisms in vitro and in vivo. First, Pin1 was verified in the NAFLD model in vitro using MCD diet-fed mice by Western Blot, RT-qPCR and immunohistochemistry (IHC) assays. In the in vitro study, we used the oleic acid (OA) stimulation-induced lipid accumulation model and examined the lipid accumulation in each group of cells by oil red O staining as well as BODIPY staining. The results showed that knockdown of Pin1 inhibited lipid accumulation in hepatocytes in an in vitro lipid accumulation model and improved lipid indices and liver injury levels. Moreover, in vivo, WT and Pin1-KO mice were fed a methionine-choline deficient (MCD) diet for 4 weeks to induce the NAFLD model. The effects of Pin1 on lipid accumulation, hepatic fibrosis, and oxidative stress were evaluated by biochemical analysis, glucose and insulin tolerance tests, histological analysis, IHC, RT-qPCR and Western blot assays. The results indicate that Pin1 knockdown significantly alleviated hepatic steatosis, fibrosis and inflammation in MCD-induced NAFLD mice, improved glucose tolerance and alleviated insulin resistance in mice. Further studies showed that the AMPK/ACC1 signalling pathway might take part in the process by which Pin1 regulates NAFLD, as evidenced by the inhibition of the AMPK/ACC1 pathway. In addition, immunofluorescence (IF), coimmunoprecipitation (Co-IP) and GST pull-down experiments also showed that Pin1 interacts directly with ACC1 and inhibits ACC1 phosphorylation levels. Our study suggests that Pin1 promotes NAFLD progression by inhibiting the activation of the AMPK/ACC1 signalling pathway, and it is possible that this effect is achieved by Pin1 interacting with ACC1 and inhibiting the phosphorylation of ACC1.

Identification of genetic markers associated with hyperketonemia patterns in early lactation Holstein cows

Ketosis, evidenced by hyperketonemia with elevated blood β-hydroxybutyrate (BHB) levels, is a significant metabolic disorder of dairy cattle, typically diagnosed within the first 6 weeks post-calving when high energy levels are essential to milk production. Our study aimed to identify genetic markers linked to hyperketonemia (HYK) patterns in Holstein cows during early lactation and compare these to HYK-negative cows. We screened 964 cows for HYK using a threshold of BHB ≥1.2 mmol/L during the first 2 weeks postpartum (screening period, SP). Cows that tested negative initially were retested the following week. Cows were deemed HYK-negative (CON group) if BHB levels were below 1.2 mmol/L in both tests, while those with BHB levels exceeding this threshold at any test were treated and classified as HYK-positive (HYK+). Post-treatment, HYK+ cows were monitored for two-week follow-up period (FP) and classified based on their recovery: cured (CUR; consistently low BHB), recurrent (REC; fluctuating BHB levels), severe (SEV; high initial BHB that decreased), or chronic (CHR; persistently high BHB). Using 489 cows that were genotyped, a GWAS was conducted using GCTA software, revealing significant associations of several SNPs across different HYK patterns when compared to the CON group. These SNPs were primarily linked to genes affecting milk traits and were enriched in biological pathways relevant to protein glycosylation, inflammatory response, glucose homeostasis, and fatty acid synthesis. Our findings highlight genomic regions, potential candidate genes, and biological pathways related to ketosis, underscoring potential targets for improving health management in dairy cattle. These insights could lead to better strategies for managing ketosis through genetic selection, ultimately enhancing dairy cattle welfare and productivity. Further research with a larger number of cows is recommended to validate these findings and help confirm the implicated SNPs and genes.

Loureirin B ameliorates cholestatic liver fibrosis via AKT/mTOR/ATG7-mediated autophagy of hepatic stellate cells

AIM OF THE STUDY

Chronic cholestasis leads to liver fibrosis, which lacks effective treatment. In this study, we investigated the role and mechanisms of action of loureirin B (LB) in cholestatic liver fibrosis.

MATERIALS AND METHODS

Bile duct ligation (BDL)-induced hepatic fibrosis mice were used as in vivo models. Transforming growth factor-β1 (TGF-β1)-pretreated HSC-T6 cells were used to explore the mechanism by which LB attenuates liver fibrosis in vitro. RNA sequencing, quantitative PCR (qPCR), western blotting, immunohistochemistry and immunofluorescence were performed to detect the fibrosis markers and measure autophagy levels. Flow cytometry, cell counting kit-8 (CCK-8) assay, and 5'-ethynyl-2'-deoxyuridine (EdU) assay were conducted to detect cell proliferation and viability. GFP-RFP-LC3 adenovirus, autophagy-related protein 7 (ATG7) siRNA, and bafilomycin A1 (BafA1) were used to verify autophagic flux.

RESULTS

Our results showed that LB ameliorates liver injury, inhibits collagen deposition, and decreases the expressions of fibrosis-related markers in BDL-induced mouse livers. In vitro, we found that LB inhibited proliferation and migration, promoted apoptosis, and inhibited the activation of HSC-T6 cells pretreated with TGF-β1. RNA sequencing analysis of HSC-T6 cells showed that LB treatment predominantly targeted autophagy-related pathways. Further protein analysis indicated that LB downregulated the expression of phosphorylated AKT (p-AKT) and phosphorylated mTOR (p-mTOR), and upregulated LC3-II, p62, and ATG7 both in vivo and in vitro. Intriguingly, ATG7 inactivation reversed the antifibrotic effects of LB on HSC-T6 cells.

CONCLUSIONS

LB can improve BDL-induced liver fibrosis by inhibiting the activation and proliferation of HSCs and is expected to be a promising antifibrotic drug.

A Systematic Review of Proteomics in Obesity: Unpacking the Molecular Puzzle

PURPOSE OF REVIEW

The present study aims to review the existing literature to identify pathophysiological proteins in obesity by conducting a systematic review of proteomics studies. Proteomics may reveal the mechanisms of obesity development and clarify the links between obesity and related diseases, improving our comprehension of obesity and its clinical implications.

RECENT FINDINGS

Most of the molecular events implicated in obesity development remain incomplete. Proteomics stands as a powerful tool for elucidating the intricate interactions among proteins in the context of obesity. This methodology has the potential to identify proteins involved in pathological processes and to evaluate changes in protein abundance during obesity development, contributing to the identification of early disease predisposition, monitoring the effectiveness of interventions and improving disease management overall. Despite many non-targeted proteomic studies exploring obesity, a comprehensive and up-to-date systematic review of the molecular events implicated in obesity development is lacking. The lack of such a review presents a significant challenge for researchers trying to interpret the existing literature. This systematic review was conducted following the PRISMA guidelines and included sixteen human proteomic studies, each of which delineated proteins exhibiting significant alterations in obesity. A total of 41 proteins were reported to be altered in obesity by at least two or more studies. These proteins were involved in metabolic pathways, oxidative stress responses, inflammatory processes, protein folding, coagulation, as well as structure/cytoskeleton. Many of the identified proteomic biomarkers of obesity have also been reported to be dysregulated in obesity-related disease. Among them, seven proteins, which belong to metabolic pathways (aldehyde dehydrogenase and apolipoprotein A1), the chaperone family (albumin, heat shock protein beta 1, protein disulfide-isomerase A3) and oxidative stress and inflammation proteins (catalase and complement C3), could potentially serve as biomarkers for the progression of obesity and the development of comorbidities, contributing to personalized medicine in the field of obesity. Our systematic review in proteomics represents a substantial step forward in unravelling the complexities of protein alterations associated with obesity. It provides valuable insights into the pathophysiological mechanisms underlying obesity, thereby opening avenues for the discovery of potential biomarkers and the development of personalized medicine in obesity.

FOXA1-Driven pathways exacerbate Radiotherapy-Induced kidney injury in colorectal cancer

OBJECTIVE

This study aimed to investigate the role of FOXA1 in acute kidney injury (AKI) induced by radiotherapy in colorectal cancer. Although FOXA1 is known to be aberrantly expressed in malignant tumors, its contribution to AKI remains unclear. This study aimed to explore the involvement of FOXA1 in AKI induced by radiotherapy in colorectal cancer and its influence on the regulation of downstream target genes.

METHODS

Firstly, a transcriptome analysis was performed on mice to establish a radiation-induced AKI model, and qPCR was used to determine the expression of FOXA1 in renal cell injury models induced by X-ray irradiation. Additionally, FOXA1 was silenced using lentiviral vectors to investigate its effects on the apoptosis of mice with radiation-induced AKI and HK-2 cells. Next, bioinformatics analysis and various experimental validation methods such as ChIP assays, co-immunoprecipitation, and dual-luciferase reporter assays were employed to explore the relationship between FOXA1 and the downstream regulatory factors ITCH promoter and the ubiquitin ligase-degradable TXNIP. Finally, lentiviral overexpression or knockout techniques were used to investigate the impact of the FOXA1/ITCH/TXNIP axis on oxidative stress and the activation of inflammatory body NLRP3.

RESULTS

This study revealed that FOXA1 was significantly upregulated in the renal tissues of mice with radiation-induced AKI and in the injured HK-2 cells. Furthermore, in vitro cell experiments and animal experiments demonstrated that FOXA1 suppressed the transcription of the E3 ubiquitin ligase ITCH, thereby promoting apoptosis of renal tubular cells and causing renal tissue damage. Further in vivo animal experiments confirmed that TXNIP, a protein degraded by ITCH ubiquitination, could inhibit oxidative stress and the activation of NLRP3 inflammasome in the AKI mouse model.

CONCLUSION

FOXA1 enhances oxidative stress, cell apoptosis, and NLRP3 inflammasome activation by regulating the ITCH/TXNIP axis, thereby exacerbating radiotherapy-induced AKI.

Targeted inhibition of autophagy in hepatic stellate cells by hydroxychloroquine: An effective therapeutic approach for the treatment of liver fibrosis

BACKGROUND AND PURPOSE

Liver fibrosis is a wound-healing reaction which is the main cause of chronic liver diseases worldwide. The activated hepatic stellate cell (aHSC) is the main driving factor in the development of liver fibrosis. Inhibiting autophagy of aHSC can prevent the progression of liver fibrosis, but inhibiting autophagy of other liver cells has opposite effects. Hence, targeted inhibition of autophagy in aHSC is quite necessary for the treatment of liver fibrosis, which prompts us to explore the targeted delivery system of small molecule autophagy inhibitor hydroxychloroquine (HCQ) that can target aHSC and alleviate the liver fibrosis.

METHODS

The delivery system of HCQ@retinol-liposome nanoparticles (HCQ@ROL-LNPs) targeting aHSC was constructed by the film dispersion and pH-gradient method. TGF-β-induced HSC activation and thioacetamide (TAA)-induced liver fibrosis mice model were established, and the targeting ability and therapeutic effect of HCQ@ROL-LNPs in liver fibrosis were studied subsequently in vitro and in vivo.

RESULTS

HCQ@ROL-LNPs have good homogeneity and stability. They inhibited the autophagy of aHSC selectively by HCQ and reduced the deposition of extracellular matrix (ECM) and the damage to other liver cells. Compared with the free HCQ and HCQ@LNPs, HCQ@ROL-LNPs had good targeting ability, showing enhanced therapeutic effect and low toxicity to other organs.

CONCLUSION

Construction of HCQ@ROL-LNPs delivery system lays a theoretical and experimental foundation for the treatment of liver fibrosis and promotes the development of clinical therapeutic drugs for liver diseases.

LncRNA AC005165.1 Alleviates IL-1β-Induced Osteoarthritis via miR-199a-3p/TXNIP Axis

Osteoarthritis (OA) is a chronic musculoskeletal disease and often causes impaired joint mobility and disability. Long noncoding RNAs (lncRNAs) play pivotal roles in OA development. This study was done to explore the role and mechanism of the lncRNA AC005165.1 in the cell model of interleukin-1β (IL)-1β-treated chondrocytes. This study recruited 20 surgically treated OA patients and 12 age- and gender-matched controls. Real-time reverse transcription quantitative polymerase chain reaction was used to examine the expression levels of AC005165.1, miR-199a-3p, and thioredoxin-interacting protein (TXNIP) in articular cartilage of patients and IL-1β-treated human chondrocytes. Cell viability and apoptosis were evaluated by cell counting kit-8 and flow cytometry assays, respectively. The protein levels of inflammatory cytokines were assessed by western blotting. Enzyme-linked immunosorbent assay was conducted to detect the concentrations of the inflammatory cytokines in chondrocytes. Luciferase reporter assay and Pearson's correlation analysis were used for analyzing the interaction and the correlation among AC005165.1, miR-199a-3p, and TXNIP. AC005165.1 expression was downregulated in cartilage of OA patients and chondrocytes treated with IL-1β, compared to that in the control groups. AC005165.1 knockdown increased apoptosis and aggravated inflammatory response in IL-1β-treated chondrocytes. AC005165.1 interacted with miR-199a-3p, and TXNIP was targeted by miR-199a-3p. In rescue assay, miR-199a-3p knockdown and TXNIP overexpression significantly reduced apoptosis and mitigated inflammatory response in IL-1β-treated chondrocytes with AC005165.1 knockdown. AC005165.1 knockdown promoted apoptosis and inflammatory response in IL-1β-treated chondrocytes via the miR-199a-3p/TXNIP axis.

Oleic and linoleic acids promote chondrocyte apoptosis by inhibiting autophagy via downregulation of SIRT1/FOXO1 signaling

Osteoarthritis (OA) is a complex joint disease that currently has no cure. OA involves metabolic disorders in chondrocytes and an imbalance between autophagy and apoptosis. As a common risk factor for OA, obesity induces changes in the fatty acid composition of synovial fluid, thereby disturbing chondrocyte homeostasis. However, whether unsaturated fatty acids affect the development of OA by regulating chondrocyte autophagy remains unclear. This study aimed to determine the effects of oleic and linoleic acids on chondrocyte autophagy and related mechanisms. Based on the mass spectrometry results, the levels of multiple unsaturated fatty acids, including oleic and linoleic acids, in the synovial fluid of patients with OA and obesity were significantly higher than those in patients with OA only. Moreover, we found that FOXO1 and SIRT1 were downregulated after oleic and linoleic acids treatment of chondrocytes, which inhibited chondrocyte autophagy. Importantly, the upregulation of SIRT1 and FOXO1 expression not only increased the level of autophagy but also improved the expression of chondrocyte extracellular matrix proteins. Furthermore, upregulated SIRT1 and FOXO1 expression alleviated the destruction of the articular cartilage in an OA rat model. Our results suggest that SIRT1/FOXO1 signaling can alleviate oleic acid- and linoleic acid-induced cartilage degradation both in vitro and in vivo and that the SIRT1/FOXO1 pathway may serve as an effective treatment target for inhibiting OA progression.

Knockdown of TXNIP alleviates gestational diabetes mellitus by activating autophagy to regulate cell proliferation and apoptosis in high glucose-treated trophoblasts

Dysregulated thioredoxin-interacting protein (TXNIP) has been observed in women with gestational diabetes mellitus (GDM), but the specific role of TXNIP in GDM and the underlying mechanism remain unclear. HTR-8/SVneo cells were treated with high glucose to mimic the injured trophoblasts of GDM. In vitro, TXNIP knockdown was performed by siRNA. RTqPCR was performed to determine the expression of the corresponding genes. Cell proliferation and apoptosis were measured using CCK-8, EdU and Annexin V/PI assays. The autophagosome number was assessed using transmission electron microscopy. The expression of the autophagy substrate sequestosome 1 (P62) was evaluated by immunofluorescence. Autophagy-related proteins, including P62, light chain 3 (LC3)-I, and LC3-II, were analysed by Western blotting. HTR-8/Svneo cells treated with high glucose demonstrated reduced proliferation, increased apoptosis, decreased autophagosome formation and overall decreased autophagy. However, knockdown of TXNIP reversed the effects of HG on HTR-8/Svneo cells. However, the effect of TXNIP knockdown on HG-treated HTR-8/Svneo cells was inhibited by 3-methyladenine (3-MA) (widely used as an inhibitor of autophagy). We concluded that knockdown of TXNIP has the potential to enhance the activity of high glucose-treated human trophoblasts through autophagic activation, thereby improving pregnancy outcomes in patients with GDM.

Molecular Regulation of Transforming Growth Factor-β1-induced Thioredoxin-interacting Protein Ubiquitination and Proteasomal Degradation in Lung Fibroblasts: Implication in Pulmonary Fibrosis

Thioredoxin-interacting protein (TXNIP) plays a critical role in regulation of cellular redox reactions and inflammatory responses by interacting with thioredoxin (TRX) or the inflammasome. The role of TXNIP in lung fibrosis and molecular regulation of its stability have not been well studied. Therefore, here we investigated the molecular regulation of TXNIP stability and its role in TGF-β1-mediated signaling in lung fibroblasts. TXNIP protein levels were significantly decreased in lung tissues from bleomycin-challenged mice. Overexpression of TXNIP attenuated transforming growth factor-β1 (TGF-β1)-induced phosphorylation of Smad2/3 and fibronectin expression in lung fibroblasts, suggesting that decrease in TXNIP may contribute to the pathogenesis of lung fibrosis. Further, we observed that TGF-β1 lowered TXNIP protein levels, while TXNIP mRNA levels were unaltered by TGF-β1 exposure. TGF-β1 induced TXNIP degradation via the ubiquitin-proteasome system. A serine residue mutant (TNXIP-S308A) was resistant to TGF-β1-induced degradation. Furthermore, downregulationof ubiquitin-specific protease-13 (USP13) promoted the TGF-β1-induced TXNIP ubiquitination and degradation. Mechanistic studies revealed that USP13 targeted and deubiquitinated TXNIP. The results of this study revealed that the decrease of TXNIP in lungs apparently contributes to the pathogenesis of pulmonary fibrosis and that USP13 can target TXNP for deubiquitination and regulate its stability.

Structure-based design and synthesis of anti-fibrotic compounds derived from para-positioned 3,4,5-trisubstituted benzene

Liver fibrosis is an abnormal wound-healing response to liver injuries. It can lead to liver cirrhosis, and even liver cancer and liver failure. There is a lack of treatment for liver fibrosis and it is of great importance to develop anti-fibrotic drugs. A pivotal event in the process of developing liver fibrosis is the activation of hepatic stellate cells (HSCs), in which the nuclear receptor Nur77 plays a crucial role. This study aimed to develop novel anti-fibrotic agents with Nur77 as the drug target by modifying the structure of THPN, a Nur77-binding and anti-melanoma compound. Specifically, a series of para-positioned 3,4,5-trisubstituted benzene ring compounds with long-chain backbone were generated and tested for anti-fibrotic activity. Among these compounds, compound A8 was with the most potent and Nur77-dependent inhibitory activity against TGF-β1-induced activation of HSCs. In a crystal structure analysis, compound A8 bound Nur77 in a peg-in-hole mode as THPN did but adopted a different conformation that could interfere the Nur77 interaction with AKT, which was previous shown to be important for an anti-fibrotic activity. In a cell-based assay, compound A8 indeed impeded the interaction between Nur77 and AKT leading to the stabilization of Nur77 without the activation of AKT. In a mouse model, compound A8 effectively suppressed the activation of AKT signaling pathway and up-regulated the cellular level of Nur77 to attenuate the HSCs activation and ameliorate liver fibrosis with no significant toxic side effects. Collectively, this work demonstrated that Nur77-targeting compound A8 is a promising anti-fibrotic drug candidate.

Drug targets regulate systemic metabolism and provide new horizons to treat nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH), is the advanced stage of nonalcoholic fatty liver disease (NAFLD) with rapidly rising global prevalence. It is featured with severe hepatocyte apoptosis, inflammation and hepatic lipogenesis. The drugs directly targeting the processes of steatosis, inflammation and fibrosis are currently under clinical investigation. Nevertheless, the long-term ineffectiveness and remarkable adverse effects are well documented, and new concepts are required to tackle with the root causes of NASH progression. We critically assess the recently validated drug targets that regulate the systemic metabolism to ameliorate NASH. Thermogenesis promoted by mitochondrial uncouplers restores systemic energy expenditure. Furthermore, regulation of mitochondrial proteases and proteins that are pivotal for intracellular metabolic homeostasis normalize mitochondrial function. Secreted proteins also improve systemic metabolism, and NASH is ameliorated by agonizing receptors of secreted proteins with small molecules. We analyze the drug design, the advantages and shortcomings of these novel drug candidates. Meanwhile, the structural modification of current NASH therapeutics significantly increased their selectivity, efficacy and safety. Furthermore, the arising CRISPR-Cas9 screen strategy on liver organoids has enabled the identification of new genes that mediate lipid metabolism, which may serve as promising drug targets. In summary, this article discusses the in-depth novel mechanisms and the multidisciplinary approaches, and they provide new horizons to treat NASH.

Cediranib ameliorates portal hypertensive syndrome via inhibition of VEGFR-2 signaling in cirrhotic rats

Portal hypertension (PHT) is a syndrome caused by systemic and portal hemodynamic disturbances with the progression of cirrhosis. However, the exact mechanisms regulating angiogenesis-related responses in PHT remain unclear. Cediranib is a potent inhibitor of vascular endothelial growth factor receptor (VEGFR) tyrosine kinases, exhibiting a greater affinity for VEGFR-2. Liver cirrhosis was induced by common bile duct ligation (BDL) in Sprague-Dawley rats. Sham-operated rats were controls. BDL and sham rats were randomly allocated to receive Cediranib or vehicle after BDL. On the 28th day, portal hypertension related parameters were surveyed. Cediranib treatment could significantly reduce the portal pressure (PP) in BDL rats, while it did not affect the mean arterial pressure (MAP) in sham groups and BDL groups. Cediranib treatment could significantly affect the stroke volume (SV), cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR), superior mesenteric artery (SMA) flow and SMA resistance in BDL groups and BDL with Cediranib groups. Cediranib treatment could improve the mesenteric vascular remodeling and contractility. Cediranib treatment significantly reduced mesenteric vascular density. And phospho-VEGFR-2 was significantly downregulated by Cediranib. On the other hand, phospho-endothelial Nitric Oxide Synthases (phospho-eNOS) expressions were upregulated. Cediranib not only improved splanchnic hemodynamics, extrahepatic vascular remodeling and vasodilation, but also alleviated intrahepatic fibrosis and collagen deposition significantly. Cediranib treatment could reduce intrahepatic angiogenesis between BDL-vehicle and BDL-Cediranib rats. In conclusion, Cediranib could improve extrahepatic hyperdynamic circulation by inhibiting extrahepatic angiogenesis through inhibition of the VEGFR-2 signaling pathway, portal collateral circulation formation, as well as eNOS-mediated vasodilatation and vascular remodeling, and at the same time, Cediranib improved intrahepatic fibrogenesis and angiogenesis, which together alleviate cirrhotic PHT syndrome.

Bafilomycin A1 Molecular Effect on ATPase Activity of Subcellular Fraction of Human Colorectal Cancer and Rat Liver

Bafilomycin A1 inhibits V-type H+ ATPases on the molecular level, which acidifies endo-lysosomes. The main objective of the study was to assess the effect of bafilomycin A1 on Ca2+ content, NAADP-induced Ca2+ release, and ATPase activity in rat hepatocytes and human colon cancer samples. Chlortetracycline (CTC) was used for a quantitative measure of stored calcium in permeabilized rat hepatocytes. ATPase activity was determined by orthophosphate content released after ATP hydrolysis in subcellular post-mitochondrial fraction obtained from rat liver as well as from patients' samples of colon mucosa and colorectal cancer samples. In rat hepatocytes, bafilomycin A1 decreased stored Ca2+ and prevented the effect of NAADP on stored Ca2+. This effect was dependent on EGTA-Ca2+ buffers in the medium. Bafilomycin A1 significantly increased the activity of Ca2+ ATPases of endoplasmic reticulum (EPR), but not plasma membrane (PM) Ca2+ ATPases in rat liver. Bafilomycin A1 also prevented the effect of NAADP on these pumps. In addition, bafilomycin A1 reduced Na+/K+ ATPase activity and increased basal Mg2+ ATPase activity in the subcellular fraction of rat liver. Concomitant administration of bafilomycin A1 and NAADP enhanced these effects. Bafilomycin A1 increased the activity of the Ca2+ ATPase of EPR in the subcellular fraction of normal human colon mucosa and also in colon cancer tissue samples. In contrast, it decreased Ca2+ ATPase PM activity in samples of normal human colon mucosa and caused no changes in colon cancer. Bafilomycin A1 decreased Na+/K+ ATPase activity and increased basal Mg2+ ATPase activity in normal colon mucosa samples and in human colon cancer samples. It can be concluded that bafilomycin A1 targets NAADP-sensitive acidic Ca2+ stores, effectively modulates ATPase activity, and assumes the link between acidic stores and EPR. Bafilomycin A1 may be useful for cancer therapy.

Hepatic Zbtb18 (Zinc Finger and BTB Domain Containing 18) alleviates hepatic steatohepatitis via FXR (Farnesoid X Receptor)

A lasting imbalance between fatty acid synthesis and consumption leads to non-alcoholic fatty liver disease (NAFLD), coupled with hepatitis and insulin resistance. Yet the details of the underlying mechanisms are not fully understood. Here, we unraveled that the expression of the transcription factor Zbtb18 is markedly decreased in the livers of both patients and murine models of NAFLD. Hepatic Zbtb18 knockout promoted NAFLD features like impaired energy expenditure and fatty acid oxidation (FAO), and induced insulin resistance. Conversely, hepatic Zbtb18 overexpression alleviated hepato-steatosis, insulin resistance, and hyperglycemia in mice fed on a high-fat diet (HFD) or in diabetic mice. Notably, in vitro and in vivo mechanistic studies revealed that Zbtb18 transcriptional activation of Farnesoid X receptor (FXR) mediated FAO and Clathrin Heavy Chain (CLTC) protein hinders NLRP3 inflammasome activity. This key mechanism by which hepatocyte's Zbtb18 expression alleviates NAFLD and consequent liver fibrosis was further verified by FXR's deletion and forced expression in mice and cultured mouse primary hepatocytes (MPHs). Moreover, CLTC deletion significantly abrogated the hepatic Zbtb18 overexpression-driven inhibition of NLRP3 inflammasome activity in macrophages. Altogether, Zbtb18 transcriptionally activates the FXR-mediated FAO and CLTC expression, which inhibits NLRP3 inflammasome's activity alleviating inflammatory stress and insulin resistance, representing an attractive remedy for hepatic steatosis and fibrosis.

Estrogen receptor-related receptor (Esrra) induces ribosomal protein Rplp1-mediated adaptive hepatic translation during prolonged starvation

Protein translation is an energy-intensive ribosome-driven process that is reduced during nutrient scarcity to conserve cellular resources. During prolonged starvation, cells selectively translate specific proteins to enhance their survival (adaptive translation); however, this process is poorly understood. Accordingly, we analyzed protein translation and mRNA transcription by multiple methods in vitro and in vivo to investigate adaptive hepatic translation during starvation. While acute starvation suppressed protein translation in general, proteomic analysis showed that prolonged starvation selectively induced translation of lysosome and autolysosome proteins. Significantly, the expression of the orphan nuclear receptor, estrogen-related receptor alpha (Esrra) increased during prolonged starvation and served as a master regulator of this adaptive translation by transcriptionally stimulating 60S acidic ribosomal protein P1 (Rplp1) gene expression. Overexpression or siRNA knockdown of Esrra expression in vitro or in vivo led to parallel changes in Rplp1 gene expression, lysosome/autophagy protein translation, and autophagy. Remarkably, we have found that Esrra had dual functions by not only regulating transcription but also controling adaptive translation via the Esrra/Rplp1/lysosome/autophagy pathway during prolonged starvation.

Targeting DGAT1 inhibits prostate cancer cells growth by inducing autophagy flux blockage via oxidative stress

Impaired macroautophagy/autophagy flux has been implicated in the treatment of prostate cancer (PCa). However, the mechanism underlying autophagy dysregulation in PCa remains unknown. In the current study, we investigated the role of diacylglycerol acyltransferases 1 (DGAT1) and its potential effects on cellular energy homeostasis and autophagy flux in PCa. The results of immunohistochemical staining suggested that DGAT1 expression was positively corrected with tumor stage and node metastasis, indicating DGAT1 is an important factor involved in the development and progression of PCa. Furthermore, targeting DGAT1 remarkably inhibited cell proliferation in vitro and suppressed PCa growth in xenograft models by triggering severe oxidative stress and subsequently autophagy flux blockage. Mechanically, DGAT1 promoted PCa progression by maintaining cellular energy homeostasis, preserving mitochondrial function, protecting against reactive oxygen species, and subsequently promoting autophagy flux via regulating lipid droplet formation. Moreover, we found that fenofibrate exhibits as an upstream regulator of DGAT1. Fenofibrate performed its anti-PCa effect involved the aforementioned mechanisms, and partially dependent on the regulation of DGAT1. Collectively. These findings indicate that DGAT1 regulates PCa lipid droplets formation and is essential for PCa progression. Targeting DGAT1 might be a promising method to control the development and progression of PCa. Schematic representation of DGAT1 affects autophagy flux by regulating lipid homeostasis and maintaining mitochondrial function in prostate cancer (PCa). PCa is characterized up-regulation of DGAT1, leading to the translocation of free fatty acids into lipid droplets, thereby preventing PCa cell from lipotoxicity. Inhibition of DGAT1 suppresses growth of PCa by inducing oxidative stress and subsequently autophagy flux blockage. Further, the current results revealed that fenofibrate exhibits as an upstream regulator of DGAT1, and fenofibrate plays an anti-PCa role partially dependent on the regulation of DGAT1, suggesting a potential therapeutic approach to ameliorate this refractory tumor.

TXNIP in liver sinusoidal endothelial cells ameliorates alcohol-associated liver disease via nitric oxide production

Dysregulation of liver sinusoidal endothelial cell (LSEC) differentiation and function has been reported in alcohol-associated liver disease (ALD). Impaired nitric oxide (NO) production stimulates LSEC capillarization and dysfunction; however, the mechanism underlying NO production remains unclear. Here, we investigated the role of thioredoxin-interacting protein (TXNIP), an important regulator of redox homeostasis, in endothelial cell NO production and its subsequent effects on ALD progression. We found that hepatic TXNIP expression was upregulated in patients with ALD and in ethanol diet-fed mice with high expression in LSECs. Endothelial cell-specific Txnip deficiency (TxnipΔEC) in mice exacerbated alcohol-induced liver injury, inflammation, fibrosis, and hepatocellular carcinoma development. Deletion of Txnip in LSECs led to sinusoidal capillarization, downregulation of NO production, and increased release of proinflammatory cytokines and adhesion molecules, whereas TXNIP overexpression had the opposite effects. Mechanistically, TXNIP interacted with transforming growth factor β-activated kinase 1 (TAK1) and subsequently suppressed the TAK1 pathway. Inhibition of TAK1 activation restored NO production and decreased the levels of proinflammatory cytokines, thereby, blocking liver injury and inflammation in TxnipΔEC mice. Our findings indicate that upregulated TXNIP expression in LSECs serves a protective role in ameliorating ALD. Enhancing TXNIP expression could, therefore, be a potential therapeutic approach for ALD.

Sirtuins and autophagy in lipid metabolism

Sirtuins are a family of NAD+ -dependent deacetylases that regulate some important biological processes, including lipid metabolism and autophagy, through their deacetylase function. Autophagy is a new discovery in the field of lipid metabolism, which may provide a new idea for the regulation of lipid metabolism. There are many tandem parts in the regulation process of lipid metabolism and autophagy of sirtuins protein family. This paper summarized these tandem parts and proposed the possibility of sirtuins regulating lipid autophagy, as well as the interaction and synergy between sirtuins protein family. Currently, some natural drugs have been reported to affect metabolism by regulating sirtuins, some of which regulate autophagy by targeting sirtuins.

Inducible nitric oxide synthase accelerates nonalcoholic fatty liver disease progression by regulating macrophage autophagy

BACKGROUND

Cells and tissues, such as macrophages, express inducible nitric oxide synthase (INOS) after stimulation by certain factors. INOS helps mediate the macrophage inflammatory reaction, but few studies have explored how INOS affects macrophage function in nonalcoholic fatty liver disease (NAFLD).

OBJECTIVE

This study investigated the role of INOS-mediated macrophage activity in NAFLD.

METHODS

A high-fat diet was used to establish an NAFLD mouse model. After 12 weeks, blood was collected for immune cell and lipid analyses, and liver tissues were collected for pathological analyses with hematoxylin and eosin and Oil Red O staining. Peritoneal macrophages were extracted in situ, cultured in Dulbecco's modified Eagle's medium, and stimulated with palmitic acid to mimic in vivo conditions for further assays. Real-time polymerase chain reaction, western blot analysis, and immunofluorescence were used to verify the expression of target genes or proteins.

RESULTS

In the NAFLD model, INOS expression in macrophages increased, and INOS knockdown significantly decreased the number of macrophages. Pathological examinations confirmed that INOS knockdown slowed NAFLD progression and macrophage infiltration during inflammation. INOS knockdown also enhanced phagocytosis and lipid transport by macrophages, and increased the expression of autophagy-related molecules in macrophages, which improved the autophagy level, promoted apoptotic cell degradation, and maintained intracellular environment homeostasis.

CONCLUSIONS

These results indicate a correlation between INOS expression and macrophage function in NAFLD.

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.

Design, synthesis, and biological evaluation of carbonyl-hydrazine-1-carboxamide derivatives as anti-hepatic fibrosis agents targeting Nur77

Hepatic fibrosis remains a great challenge clinically. The orphan nuclear receptor Nur77 is recently suggested as the critical regulator of transforming growth factor-β (TGF-β) signaling, which plays a central role in multi-organic fibrosis. Herein, we optimized our previously reported Nur77-targeted compound 9 h for attempting to develop effective and safe anti-hepatic fibrosis agents. The critical pharmacophore scaffold of pyridine-carbonyl-hydrazine-1-carboxamide was retained, while the naphthalene ring was replaced with an aromatic ring containing pyridyl or indole groups. Four series of derivatives were thus generated, among which the compound 16f had excellent binding activity toward Nur77-LBD (KD = 470 nM) with the best inhibitory activity against the TGF- β 1 activation of hepatic stellate cells (HSCs) and low cytotoxicity to normal mice liver AML-12 cells (IC50 > 80 μM). In mice, 16f displayed potent activity against CCl4-induced liver fibrosis with improved liver function. Mechanistically, 16f-mediated inactivation of HSC and suppression of liver fibrosis were associated with its enhancement of autophagic flux in a Nur77-dependent manner. Together, 16f was identified as a potential anti-liver fibrosis agent. Our study suggests that Nur77 may serve as a critical anti-hepatic fibrosis target.

Ubiquitin-specific peptidase 25 exacerbated osteoarthritis progression through facilitating TXNIP ubiquitination and NLRP3 inflammasome activation

Several members of the ubiquitin-specific proteases (USPs) family have been revealed to regulate the progression of osteoarthritis (OA). The current study aimed to investigate the role and the underlying mechanism of USP25 in IL-1β-induced chondrocytes and OA rat model. It was discovered that IL-1β stimulation upregulated USP25, increased ROS level, and suppressed cell viability in rat chondrocytes. Besides, USP25 knockdown alleviated IL-1β-induced injury by decreasing ROS level, attenuating pyroptosis, and downregulating the expression of IL-18, NLRP3, GSDMD-N, active caspase-1, MMP-3, and MMP-13. Furthermore, we discovered that USP25 affected the IL-1β-induced injury in chondrocytes in a ROS-dependent manner. Moreover, USP25 was revealed to interact with TXNIP, and USP25 knockdown increased the ubiquitination of TXNIP. The pro-OA effect of USP25 abundance could be overturned by TXNIP suppression in IL-1β-induced chondrocytes. Finally, in vivo experiment results showed that USP25 inhibition alleviated cartilage destruction in OA rats. In conclusion, we demonstrated that USP25 stimulated the overproduction of ROS to activate the NLRP3 inflammasome via regulating TXNIP, resulting in increased pyroptosis and inflammation in OA.

VDUP1 Deficiency Promotes the Severity of DSS-Induced Colitis in Mice by Inducing Macrophage Infiltration

The loss of vitamin D3 upregulated protein 1 (VDUP1) has been implicated in the pathogenesis of various inflammation-related diseases. Notably, reduced expression of VDUP1 has been observed in clinical specimens of ulcerative colitis (UC). However, the role of VDUP1 deficiency in colitis remains unclear. In this study, we investigated the role of VDUP1 in dextran sulfate sodium (DSS)-induced experimental colitis in mice. VDUP1-deficient mice were more susceptible to DSS-induced colitis than their wild-type (WT) littermates after 2% DSS administration. VDUP1-deficient mice exhibited an increased disease activity index (DAI) and histological scores, as well as significant colonic goblet cell loss and an increase in apoptotic cells. These changes were accompanied by a significant decrease in MUC2 mRNA expression and a marked increase in proinflammatory cytokines and chemokines within damaged tissues. Furthermore, phosphorylated NF-κB p65 expression was significantly upregulated in damaged tissues in the context of VDUP1 deficiency. VDUP1 deficiency also led to significant infiltration of macrophages into the site of ulceration. An in vitro chemotaxis assay confirmed that VDUP1 deficiency enhanced bone marrow-derived macrophage (BMDM) chemotaxis induced by CCL2. Overall, this study highlights VDUP1 as a regulator of UC pathogenesis and a potential target for the future development of therapeutic strategies.

Ischemic preconditioning attenuates endoplasmic reticulum stress-dependent apoptosis of hepatocytes by regulating autophagy in hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury (HIRI) usually occurs during subtotal hepatectomy and severely damages liver function during the perioperative period. Endoplasmic reticulum stress (ERS) dependent apoptosis has been suggested to play a crucial role in HIRI progression. The present study focused on the regulatory effect of autophagy activation induced by ischemic preconditioning (IPC) on ERS-dependent apoptosis of hepatocytes in HIRI. A HIRI mouse model and oxygen-glucose deprivation/reperfusion (OGD/R) AML-12 hepatocyte cell lines were constructed to evaluate the protective effect of IPC in vivo and in vitro. The protein levels of p-eIF2α, CHOP, and cleaved caspase-12 were used to evaluate the ERS-dependent apoptosis, whereas LC3-II and p62 were considered as the autophagy activation markers. The beneficial molecular chaperones GRP78, HSP60, and HSP70 were also tested to evaluate autophagy. HIRI significantly increased ERS-dependent apoptosis markers and the number of apoptotic cells and damaged liver function. The ERS inhibitor salubrinal significantly alleviated liver injury in HIRI and OGD/R hepatocytes. Furthermore, both remote IPC and direct IPC significantly alleviated liver injury and inflammatory cell infiltration. IPC also upregulated LC3-II, downregulated p62 expression, and increased the mRNA levels of GRP78, HSP60, and HSP70 in HIRI mice and OGD/R hepatocytes, indicating the activation of autophagy by IPC. The autophagy inhibitor 3-methyladenine significantly attenuated the protective effects of IPC on ERS-dependent apoptosis and liver function, whereas the autophagy activator rapamycin mimicked the protective effects of IPC on ERS-dependent apoptosis in vivo and in vitro, suggesting a regulatory role of autophagy in ERS-dependent apoptosis. These results demonstrated that IPC could induce moderate autophagy and upregulate a few molecular chaperones to strengthen endogenous defense mechanisms, which is beneficial for alleviating ERS-dependent apoptosis and protecting hepatocytes from HIRI.

F-box only protein 2 exacerbates non-alcoholic fatty liver disease by targeting the hydroxyl CoA dehydrogenase alpha subunit

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a major health burden with an increasing global incidence. Unfortunately, the unavailability of knowledge underlying NAFLD pathogenesis inhibits effective preventive and therapeutic measures.

AIM

To explore the molecular mechanism of NAFLD.

METHODS

Whole genome sequencing (WGS) analysis was performed on liver tissues from patients with NAFLD (n = 6) and patients with normal metabolic conditions (n = 6) to identify the target genes. A NAFLD C57BL6/J mouse model induced by 16 wk of high-fat diet feeding and a hepatocyte-specific F-box only protein 2 (FBXO2) overexpression mouse model were used for in vivo studies. Plasmid transfection, co-immunoprecipitation-based mass spectrometry assays, and ubiquitination in HepG2 cells and HEK293T cells were used for in vitro studies.

RESULTS

A total of 30982 genes were detected in WGS analysis, with 649 up-regulated and 178 down-regulated. Expression of FBXO2, an E3 ligase, was upregulated in the liver tissues of patients with NAFLD. Hepatocyte-specific FBXO2 overexpression facilitated NAFLD-associated phenotypes in mice. Overexpression of FBXO2 aggravated odium oleate (OA)-induced lipid accumulation in HepG2 cells, resulting in an abnormal expression of genes related to lipid metabolism, such as fatty acid synthase, peroxisome proliferator-activated receptor alpha, and so on. In contrast, knocking down FBXO2 in HepG2 cells significantly alleviated the OA-induced lipid accumulation and aberrant expression of lipid metabolism genes. The hydroxyl CoA dehydrogenase alpha subunit (HADHA), a protein involved in oxidative stress, was a target of FBXO2-mediated ubiquitination. FBXO2 directly bound to HADHA and facilitated its proteasomal degradation in HepG2 and HEK293T cells. Supplementation with HADHA alleviated lipid accumulation caused by FBXO2 overexpression in HepG2 cells.

CONCLUSION

FBXO2 exacerbates lipid accumulation by targeting HADHA and is a potential therapeutic target for NAFLD.

Syringin alleviates hepatic fibrosis by enhancing autophagic flux and attenuating ER stress-TRIB3/SMAD3 in diabetic mice

Type 2 diabetes mellitus (T2DM) is a key risk factor for the developing of metabolic liver injury and easily evolving to advanced fibrosis. Syringin (SYR), isolated from Acanthopanax senticosus, has anti-inflammatory, anti-oxidant, and anti-apoptotic properties. However, its hepatoprotective effects and mechanisms in T2DM-induced liver fibrosis remain unclear. Here, we investigated whether syringin (SYR) could serve as a therapeutic agent for liver fibrosis and its mechanism in high-fat diet (HFD)/streptozotocin (STZ)-induced type 2 diabetic mice. C57BL/6 mice were induced with T2DM via HFD and STZ injection and treated with different doses of SYR. Serum lipid parameters and liver function indicators were measured, and hepatic histology and fibrosis were examined. The mechanism of SYR was explored through molecular analyses Results demonstrated SYR improved oral glucose tolerance, decreased the levels of ALT, AST, and AKP, and reduced hepatic lipid deposition in diabetic mice. Moreover, SYR ameliorated epithelial-to-mesenchymal transition to reverse hepatic fibrosis via suppressing TRIB3-SMAD3 interaction to restrain nuclear localization of SMAD3. Strikingly, SYR reversed hyperglycemia-induced deficiency in autophagic flux by regulation of Raptor/mTORC1, triggering nuclear translocation of TFEB to improve autophagosome-lysosomal fusion. In brief, SYR potentially ameliorates hepatic injury and fibrosis by enhancing autophagic flux and inhibing TRIB3 activation in diabetic mice.

Exogenous galanin alleviates hepatic steatosis by promoting autophagy via the AMPK-mTOR pathway

Defective autophagy-induced intracellular lipid degradation is causally associated with non-alcoholic fatty liver disease (NAFLD) development. Therefore, agents that can restore autophagy may have potential clinical application prospects on this public health issue. Galanin (GAL) is a pleiotropic peptide that regulates autophagy and is a potential drug for the treatment of NAFLD. In this study, we used an MCD-induced NAFLD mouse model in vivo and an FFA-induced HepG2 hepatocyte model in vitro to evaluate the anti-NAFLD effect of GAL. Exogenous GAL supplementation significantly attenuated lipid droplet accumulation and suppressed hepatocyte TG levels in mice and cell models. Mechanistically, Galanin-mediated reduction of lipid accumulation was positively correlated with upregulated p-AMPK, as evidenced by upregulated protein expressions of fatty acid oxidation-related gene markers (PPAR-α and CPT1A), upregulated expressions of the autophagy-related marker (LC3B), and downregulated autophagic substrate p62 levels. In FFA-treated HepG2 cells, activation of fatty acid oxidation and autophagy-related proteins by galanin was reversed by autophagy inhibitors, chloroquine, and the AMPK inhibitor. Galanin ameliorates hepatic fat accumulation by inducing autophagy and fatty acid oxidation via the AMPK/mTOR pathway.

Lp-PLA2 silencing ameliorates inflammation and autophagy in nonalcoholic steatohepatitis through inhibiting the JAK2/STAT3 pathway

Background

Nonalcoholic steatohepatitis (NASH), a common cause of liver-related morbidity and mortality worldwide, is characterized by inflammation and hepatocellular injury. Our research focuses on lipoprotein-associated phospholipase A2 (Lp-PLA2), an inflammation-related biomarker that has recently garnered interest in the context of NASH due to its potential roles in disease pathogenesis and progression.

Methods

We established a NASH mouse model using a high-fat diet (HFD) and treated it with sh-Lp-PLA2 and/or rapamycin (an mTOR inhibitor). Lp-PLA2 expression in NASH mice was detected by qRT-PCR. Serum levels of liver function parameters and inflammatory cytokines were detected using corresponding assay kits. We examined pathological changes in liver using hematoxylin-eosin, oil red O, and Masson staining, and observed autophagy through transmission electron microscopy. The protein levels of Lp-PLA2, mTOR, light chain 3 (LC3) II/I, phosphorylated Janus kinase 2 (p-JAK2)/JAK2, and phosphorylated signal transducer and activator of transcription 3 (p-STAT3)/STAT3 were determined by western blotting. Kupffer cells extracted from C57BL/6J mice were treated to replicate NASH conditions and treated with sh-Lp-PLA2, rapamycin, and/or a JAK2-inhibitor to further verify the roles and mechanisms of Lp-PLA2 in NASH.

Results

Our data indicate an upregulation of Lp-PLA2 expression in HFD-induced NASH mice. Silencing Lp-PLA2 in NASH mice reduced liver damage and inflammation markers (aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol (TC), triglycerides (TG), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6)), while increasing IL-10 levels, an anti-inflammatory cytokine. Additionally, Lp-PLA2 silencing decreased lipid and collagen accumulation and promoted autophagy. The beneficial effects of sh-Lp-PLA2 on NASH were enhanced by rapamycin. Furthermore, Lp-PLA2 silencing resulted in the downregulation of the expression of p-JAK2/JAK2 and p-STAT3/STAT3 in NASH mice. Similar results were observed in Kupffer cells treated under NASH conditions; Lp-PLA2 silencing promoted autophagy and repressed inflammation, effects which were potentiated by the addition of rapamycin or a JAK2-inhibitor.

Conclusion

Our findings suggest that silencing Lp-PLA2 promotes autophagy via deactivating the JAK2/STAT3 signaling pathway, thereby restraining NASH progression. This highlights the potential therapeutic value of targeting Lp-PLA2, adding a new dimension to our understanding of NASH pathogenesis and treatment strategies.

Therapeutic Approaches for Nonalcoholic Fatty Liver Disease: Established Targets and Drugs

Nonalcoholic fatty liver disease (NAFLD), as a multisystemic disease, is the most prevalent chronic liver disease characterized by extremely complex pathogenic mechanisms and multifactorial etiology, which often develops as a consequence of obesity, metabolic syndrome. Pathophysiological mechanisms involved in the development of NAFLD include diet, obesity, insulin resistance (IR), genetic and epigenetic determinants, intestinal dysbiosis, oxidative/nitrosative stress, autophagy dysregulation, hepatic inflammation, gut-liver axis, gut microbes, impaired mitochondrial metabolism and regulation of hepatic lipid metabolism. Some of the new drugs for the treatment of NAFLD are introduced here. All of them achieve therapeutic objectives by interfering with certain pathophysiological pathways of NAFLD, including fibroblast growth factors (FGF) analogues, peroxisome proliferator-activated receptors (PPARs) agonists, glucagon-like peptide-1 (GLP-1) agonists, G protein-coupled receptors (GPCRs), sodium-glucose cotransporter-2 inhibitors (SGLT-2i), farnesoid X receptor (FXR), fatty acid synthase inhibitor (FASNi), antioxidants, etc. This review describes some pathophysiological mechanisms of NAFLD and established targets and drugs.

mTOR in programmed cell death and its therapeutic implications

Mechanistic target of rapamycin (mTOR), a highly conserved serine/threonine kinase, is involved in cellular metabolism, protein synthesis, and cell death. Programmed cell death (PCD) assists in eliminating aging, damaged, or neoplastic cells, and is indispensable for sustaining normal growth, fighting pathogenic microorganisms, and maintaining body homeostasis. mTOR has crucial functions in the intricate signaling pathway network of multiple forms of PCD. mTOR can inhibit autophagy, which is part of PCD regulation. Cell survival is affected by mTOR through autophagy to control reactive oxygen species production and the degradation of pertinent proteins. Additionally, mTOR can regulate PCD in an autophagy-independent manner by affecting the expression levels of related genes and phosphorylating proteins. Therefore, mTOR acts through both autophagy-dependent and -independent pathways to regulate PCD. It is conceivable that mTOR exerts bidirectional regulation of PCD, such as ferroptosis, according to the complexity of signaling pathway networks, but the underlying mechanisms have not been fully explained. This review summarizes the recent advances in understanding mTOR-mediated regulatory mechanisms in PCD. Rigorous investigations into PCD-related signaling pathways have provided prospective therapeutic targets that may be clinically beneficial for treating various diseases.

Disruption of the mouse liver epitranscriptome by long-term aroclor 1260 exposure

Chronic environmental exposure to polychlorinated biphenyls (PCBs) is associated with non-alcoholic fatty liver disease (NAFLD) and exacerbated by a high fat diet (HFD). Here, chronic (34 wks.) exposure of low fat diet (LFD)-fed male mice to Aroclor 1260 (Ar1260), a non-dioxin-like (NDL) mixture of PCBs, resulted in steatohepatitis and NAFLD. Twelve hepatic RNA modifications were altered with Ar1260 exposure including reduced abundance of 2'-O-methyladenosine (Am) and N(6)-methyladenosine (m6A), in contrast to increased Am in the livers of HFD-fed, Ar1260-exposed mice reported previously. Differences in 13 RNA modifications between LFD- and HFD- fed mice, suggest that diet regulates the liver epitranscriptome. Integrated network analysis of epitranscriptomic modifications identified a NRF2 (Nfe2l2) pathway in the chronic, LFD, Ar1260-exposed livers and an NFATC4 (Nfatc4) pathway for LFD- vs. HFD-fed mice. Changes in protein abundance were validated. The results demonstrate that diet and Ar1260 exposure alter the liver epitranscriptome in pathways associated with NAFLD.

Oleic acid improves hepatic lipotoxicity injury by alleviating autophagy dysfunction

Lipotoxicity caused by excess free fatty acids, particularly saturated fatty acids (SFAs) such as palmitic acid (PA), is one of the most important pathogenesis of nonalcoholic fatty liver disease (NAFLD). However, unsaturated fatty acids (UFAs), such as oleic acid (OA), are nontoxic and can combat SFA-induced toxicity through alleviation of cell apoptosis, endoplasmic reticulum stress (ER stress) and lipids metabolism disorder. However, whether OA is able to regulate autophagy is largely unknown. So, this study aims to investigate the mechanism underlying OA mediated modulation of autophagy in hepatocytes and mice with NAFLD. In vitro, human hepatoma cell line HepG2 cells, human normal liver cells L-02 and mouse normal liver cells AML12 were treated with palmitic acid (PA)/tunicamycin (TM) or/and OA for 48 h. In vivo, C57/BL6 mice were fed with high fat diet (HFD) to induce NAFLD. And the HFD was partial replaced by olive oil to observe the protective effects of olive oil. We demonstrated that PA/TM impaired cell viability and induced cellular apoptosis in HepG2 cells and L-02 cells. Moreover, PA/TM induced autophagy impairment by reducing the nuclear translocation of transcription factor EB (TFEB) and inhibiting the activity of CTSB. However, OA substantially alleviated PA/TM induced cellular apoptosis and autophagy dysfunction in hepatocytes. Additionally, restoring autophagy function is able to reduce ER stress. Similarly, HFD for 20 weeks successfully established NAFLD model in C57/BL6 mice, and significant autophagy impairment were observed in liver tissues. Noteworthily, 30% replacement of HFD with olive oil had profoundly reversed NAFLD. It significantly impoved steatosis, and reduced autophagy dysfunction, ER stress and apoptosis in liver tissue. Conclusively, these data demonstrated that OA is able to effectively impove autophagy dysfunction under the context of both PA and ER stress inducer induced lipotoxicity, and OA mediated regulation of lysosome dysfunction through TFEB plays an important role, suggesting that the regulation of ER stress-autophagy axis is a critical mechanism in OA driven protection in NAFLD.

A novel NEDD4L-TXNIP-CHOP axis in the pathogenesis of nonalcoholic steatohepatitis

Background: Nonalcoholic steatohepatitis (NASH) is a leading cause of chronic liver diseases worldwide. There is a pressing clinical need to identify potential therapeutic targets for NASH treatment. Thioredoxin interacting protein (Txnip) is a stress responsive gene that has been implicated in the pathogenesis of NASH, but its exact role is not fully understood. Here, we investigated the liver- and gene-specific role of Txnip and its upstream/downstream signaling in the pathogenesis of NASH. Methods and Results: Using four independent NASH mouse models, we found that TXNIP protein abnormally accumulated in NASH mouse livers. A decrease in E3 ubiquitin ligase NEDD4L resulted in impaired TXNIP ubiquitination and its accumulation in the liver. TXNIP protein levels were positively correlated with that of CHOP, a major regulator of ER stress-mediated apoptosis, in NASH mouse liver. Moreover, gain- and loss-of-function studies showed that TXNIP increased protein not mRNA levels of Chop both in vitro and in vivo. Mechanistically, the C-terminus of TXNIP associated with the N-terminus of the α-helix domain of CHOP and decreased CHOP ubiquitination, thus increasing the stability of CHOP protein. Lastly, selective knockdown of Txnip by adenovirus-mediated shRNA (not targets Txnip antisense lncRNA) delivery in the livers of both young and aged NASH mice suppressed the expression of CHOP and its downstream apoptotic pathway, and ameliorated NASH by reducing hepatic apoptosis, inflammation, and fibrosis. Conclusions: Our study revealed a pathogenic role of hepatic TXNIP in NASH and identified a novel NEDD4L-TXNIP-CHOP axis in the pathogenesis of NASH.

Mechanisms of Xuefu Zhuyu Decoction in the treatment of coronary heart disease based on integrated metabolomics and network pharmacology approach

Coronary heart disease (CHD) has become the leading cause of mortality, morbidity, and disability worldwide. Though the therapeutic effect of Xuefu Zhuyu Decoction (XFZY) on CHD has been demonstrated in China, the active ingredients and molecular mechanisms of XFZY have not been elucidated. The purpose of the current study is to explore the molecular mechanisms of XFZY in the treatment of CHD via network pharmacology, metabolomics, and experimental validation. First, we established a CHD rat model by permanently ligating the left anterior descending coronary artery (LAD), and evaluated the therapeutic effect of XFZY by hemorheology and histopathology. Second, network pharmacology was employed to screen the active ingredients and potential targets of XFZY for the treatment of CHD. Metabolomic was applied to identify the molecules present in the serum after XFZY treatment. Third, the results of network pharmacology and metabolomics were further analyzed by Cytoscape to elucidate the core ingredients and pathways. Finally, the obtained key pathways were verified by transmission electron microscopy and immunofluorescence assay. The results showed that XFZY was effective in the treatment of CHD in the rat model, and the highest dose exerted the best effect. Network pharmacology analysis revealed 215 active ingredients and 129 key targets associated with XFZY treatment of CHD. These targets were enriched in pathways of cancer, lipid and atherosclerosis, fluid shear stress and atherosclerosis, proteoglycans in cancer, chemical carcinogenesis - receptor activation, HIF-1 signaling, et al. Serum metabolomic identified 1081 metabolites involved in the therapeutic effect of XFZY on CHD. These metabolites were enriched in taurine and hypotaurine metabolism, histidine metabolism, retrograde endocannabinoid signaling pathways, et al. Cytoscape analysis combining the data from serum metabolomic and network pharmacology revealed that energy metabolism as the core pathway for XFZY treatment of CHD. Electron microscope observation identified changes in the level of autophagy in the mitochondrial structure of cardiomyocytes. Immunofluorescence assay showed that the expression levels of autophagy-related proteins LC3-B and P62/SQSTM1 were consistent with the levels of autophagy observed in mitochondria. In conclusion, our findings suggest that the possible mechanisms of XFZY in the treatment of CHD are reducing the level of autophagy, improving energy metabolism, and maintaining mitochondrial homeostasis in cardiomyocytes. Our study also shows that the combined strategies of network pharmacology, metabolomics, and experimental validation may provide a powerful approach for TCM pharmacology study.

Transcriptome Sequencing Reveals Autophagy Networks in Rat Livers during the Development of NAFLD and Identifies Autophagy Hub Genes

(1) Autophagy is an important biological process in cells and is closely associated with the development and progression of non-alcoholic fatty liver disease (NAFLD). Therefore, this study aims to investigate the biological function of the autophagy hub genes, which could be used as a potential therapeutic target and diagnostic markers for NAFLD. (2) Male C57BL/6J mice were sacrificed after 16 and 38 weeks of a high-fat diet, serum biochemical indexes were detected, and liver lobules were collected for pathological observation and transcriptome sequencing. The R software was used to identify differentially expressed autophagy genes (DEGs) from the transcriptome sequencing data of mice fed with a normal diet for 38 weeks (ND38) and a high-fat diet for 38 weeks (HFD38). Gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed on the DEGs, a protein-protein interaction (PPI) network of the DEGs was established using the STRING data website, and the results were visualized through Cytoscape. (3) After 16 weeks and 38 weeks of a high-fat diet, there was a significant increase in body weight, serum total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C) and triglycerides (TG) in mice, along with lipid accumulation in the liver, which was more severe at 38 weeks than at 16 weeks. The transcriptome data showed significant changes in the expression profile of autophagy genes in the livers of NAFLD mice following a long-term high-fat diet. Among the 31 differentially expressed autophagy-related genes, 13 were upregulated and 18 were downregulated. GO and KEGG pathway analysis revealed that these DEGs were primarily involved in autophagy, cholesterol transport, triglyceride metabolism, apoptosis, the FoxO signaling pathway, the p53 signaling pathway and the IL-17 signaling pathway. Four hub genes were identified by the PPI network analysis, of which Irs2, Pnpla2 and Plin2 were significantly downregulated, while Srebf2 was significantly upregulated by the 38-week high-fat diet. (4) The hub genes Irs2, Pnpla2, Srebf2 and Plin2 may serve as key therapeutic targets and early diagnostic markers in the progression of NAFLD.

USP10 Alleviates Palmitic Acid-induced Steatosis through Autophagy in HepG2 Cells

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease caused by over-nutrition. Impaired autophagy is closely related to NAFLD progression. Recently, ubiquitin-specific peptidase-10 (USP10) was reported to ameliorate hepatic steatosis, but the underlying mechanism is still unclear. In view of the potential effects of USP10 on autophagy, we investigated whether USP10 alleviated steatosis through autophagy.

METHODS

HepG2 cells were treated with palmitic acid (PA) to model NAFLD in vitro. Lentivirus was used to regulate USP10 level in cells. Autophagic regulators were used to autophagic progression in cells. Western blotting, real-time fluorescence quantitative polymerase chain reaction, lipid drop staining and immunofluorescent staining were performed to determine the effect of USP10 on lipid autophagy. Student's t-test and Tukey's post hoc test were used to compare the means among groups.

RESULTS

PA induced cellular steatosis with dependance on autophagy. USP10 overexpression alleviated PA-induced steatosis, restored autophagic activity, promoted autophagic flux, including synthesis and degradation of autophagosomes, and lipid-targeted autophagy. In the presence of autophagy inhibitors, the protective effectiveness of USP10 on steatosis decreased. Furthermore, the specific inhibitor to C-jun N-terminal protein kinase-1 (JNK1), DB07268, abolished USP10-induced autophagy. However, during early stage inhibition of JNK1, compensatory expression of tuberous sclerosis complex-2 (TSC2) maintained autophagy. The degree of TSC2-to-JNK1 compensation was positively associated with USP10 level. Functionally, JNK1 and TSC2 were involved in the lipid-lowering effect of USP10.

CONCLUSIONS

USP10 alleviated hepatocellular steatosis in autophagy-dependent manner. JNK1/TSC2 signaling pathways were required for USP10-induced autophagy.