Leukemia inhibitory factor protects against liver steatosis in nonalcoholic fatty liver disease patients and obese mice

Leukemia inhibitory factor (LIF) receptor amplifies pathogenic activation of fibroblasts in lung fibrosis

Fibrosis drives end-organ damage in many diseases. However, clinical trials targeting individual upstream activators of fibroblasts, such as TGFβ, have largely failed. Here, we target the leukemia inhibitory factor receptor (LIFR) as an "autocrine master amplifier" of multiple upstream activators of lung fibroblasts. In idiopathic pulmonary fibrosis (IPF), the most common fibrotic lung disease, we found that lung myofibroblasts had high LIF expression, and the fibroblasts in fibroblastic foci coexpressed LIF and LIFR. In IPF, fibroblastic foci are the "leading edge" of fibrosis and a key site of disease pathogenesis. TGFβ1, one of the principal drivers of fibrosis, up-regulated LIF expression in IPF fibroblasts. We found that TGFβ1, IL-4, and IL-13 stimulations of fibroblasts require the LIF-LIFR axis to evoke a strong fibrogenic effector response in fibroblasts. In vitro antibody blockade of LIFR on IPF lung fibroblasts reduced the induction of profibrotic genes after TGFβ1 stimulation. Silencing LIF and LIFR reduced profibrotic fibroblast activation following TGFβ1, IL-4, and IL-13 stimulations. We also demonstrated that LIFR amplified profibrotic stimuli in precision-cut lung slices from IPF patients. These LIFR signals were transduced via JAK2, and STAT1 in IPF lung fibroblasts. Together, we find that LIFR drives an autocrine circuit that amplifies and sustains pathogenic activation of IPF fibroblasts. Targeting a single, downstream master amplifier on fibroblasts, like LIFR, is an alternative therapeutic strategy that simultaneously attenuates the profibrotic effects of multiple upstream stimuli.

Relation of 91 Circulating Inflammatory Proteins to Nonalcoholic Fatty Liver Disease: A Two-Sample Mendelian Randomisation Study

Increasingly, emerging research evidence has demonstrated that nonalcoholic fatty liver disease (NAFLD) is a disease closely associated with systemic inflammation. However, the specific upstream inflammatory factors engaged in the pathogenesis of NAFLD remain unclear. Our study aimed to identify the inflammatory regulators causally associated with NAFLD pathogenesis through Mendelian randomisation. A two-sample Mendelian randomisation method was applied to analyse the causal association between 91 circulating inflammatory proteins and NAFLD. Data on circulating inflammatory proteins were derived from samples of European ancestry (14,824 samples) and NAFLD data were obtained from the FinnGen consortium (2025 cases and 284,826 controls). Instrumental variables were selected from the genetic variance and F-statistics were calculated to avoid bias. We adopted the random-effects inverse variance weighting (IVW) method as our primary analytical approach. Supplementary analyses were also implemented, including weighted median, MR-Egger and weighted mode. Moreover, we conducted pleiotropy and heterogeneity analyses to validate the accuracy of the findings. The application of Mendelian randomisation analysis identified four inflammatory factors that might be causally associated with NAFLD at the genetic level. Elevated levels of eotaxin (or = 1.27, 95% CI: 1.05-1.53, p = 0.014), osteoprotegerin (OPG) (or = 1.29, 1.03-1.60, p = 0.023) and TNFRSF9 (or = 1.32, 95% CI: 1.06-1.64, p = 0.014) may be causally related to an increasing risk of NAFLD. Conversely, heightened leukaemia inhibitory factor (LIF) levels (or = 0.63, 0.44-0.92, p = 0.016) were linked to a lower risk of NAFLD onset. There was no causal relationship between levels of other circulating inflammatory proteins and NAFLD. Our analysis uncovered four upstream inflammatory factors genetically associated with the pathogenesis of NAFLD. These results highlight the potential involvement of inflammation in NAFLD, which provides partial insights for further research in this field in the future.

Gut microbiota and their relationship with circulating adipokines in an acute hepatic encephalopathy mouse model induced by surgical bile duct ligation

Background and aims

Various studies have shown the importance of the gut microbiota in human health. However, little is known about gut microbiome patterns and their effect on circulating adipo-myokine levels in hepatic encephalopathy (HE). We investigated the relationship between the gut microbiota and adipo-myokine levels using a mouse model of HE induced by surgical bile duct ligation (BDL).

Methods and results

Wild-type C57BL/6J mice were subjected to sham surgery or BDL. Severe body weight loss, suppressed feed intake, and liver failure were observed in BDL mice compared with sham control mice. Additionally, changes in gut microbial communities and serum adipo-myokine levels were noted in BDL mice. In the BDL mouse gut, we identified 15 differentially abundant taxa including the phylum Verrucomicrobiota, the classes Actinomycetes and Verrucomicrobiae, the order Verrucomicrobiales, the families Akkermansiaceae, Bacteroidaceae, Rikenellaceae, and Oscillospiraceae, the genera Alistipes, Akkermansia, Muribaculum, and Phocaeicola, and the species Akkermansia muciniphila, Alistipes okayasuensis, and Muribaculum gordoncarteri by LEfSe analysis (LDA score≥4.0). Higher levels of certain adipo-myokines such as BDNF were detected in the serum of BDL mice. Spearman correlation analysis revealed that certain adipo-myokines (e.g., FSTL1) were positively correlated with the class Actinomycetes, the family Rikenellaceae, the genus Alistipes, and the species Alistipes okayasuensis. Interestingly, A. okayasuensis and M. gordoncarteri, recently isolated microbes, showed richness in the gut of BDL mice and demonstrated positive correlations with adipo-myokines such as FGF21.

Conclusions

Overall, our results suggest that alteration of the gut microbiota in patients with HE may be closely correlated to the levels of adipo-myokines in the blood.

Leukemia inhibitory factor (LIF) receptor amplifies pathogenic activation of fibroblasts in lung fibrosis

Fibrosis drives end-organ damage in many diseases. However, clinical trials targeting individual upstream activators of fibroblasts, such as TGFβ, have largely failed. Here, we target the leukemia inhibitory factor receptor (LIFR) as a "master amplifier" of multiple upstream activators of lung fibroblasts. In idiopathic pulmonary fibrosis (IPF), the most common fibrotic lung disease, we found that lung myofibroblasts had high LIF expression. Further, TGFβ1, one of the key drivers of fibrosis, upregulated LIF expression in IPF fibroblasts. In vitro anti-LIFR antibody blocking on human IPF lung fibroblasts reduced induction of profibrotic genes downstream of TGFβ1, IL-4 and IL-13. Further, siRNA silencing of LIFR in IPF precision cut lung slices reduced expression of fibrotic proteins. Together, we find that LIFR drives an autocrine positive feedback loop that amplifies and sustains pathogenic activation of IPF fibroblasts downstream of multiple external stimuli, implicating LIFR as a therapeutic target in fibrosis.

Significance Statement

Fibroblasts have a central role in the pathogenesis of fibrotic diseases. However, due to in part to multiple profibrotic stimuli, targeting a single activator of fibroblasts, like TGFβ, has not yielded successful clinical treatments. We hypothesized that a more effective therapeutic strategy is identifying a downstream "master amplifier" of a range of upstream profibrotic stimuli. This study identifies the leukemia inhibitory factor receptor (LIFR) on fibrotic lung fibroblasts amplifies multiple profibrotic stimuli, such as IL-13 and TGFβ. Blocking LIFR reduced fibrosis in ex vivo lung tissue from patients with idiopathic pulmonary fibrosis (IPF). LIFR, acting as a master amplifier downstream of fibroblast activation, offers an alternative therapeutic strategy for fibrotic diseases.

Association Between Metabolic Dysfunction-Associated Fatty Liver Disease and MACCEs in Patients with Diabetic Foot Ulcers: An Ambispective Longitudinal Cohort Study

Aim

Metabolic dysfunction-related fatty liver disease (MAFLD) is closely related to metabolic disorders. However, the relationship between MAFLD and the prognosis in diabetic foot ulcers (DFUs) remains unclear. This study aimed to explore the association between MAFLD and the risk of major adverse cardiac and cerebral events (MACCEs) in patients with DFUs.

Methods

889 inpatients with DFUs (PEDIS/TEXAS mild and above) were included in this study from 2013 to 2023. All participants were placed into non-MAFLD (n = 643) and MAFLD (n = 246) groups and followed up every 6 months for 10.9 years with a median of 63 months through in-person outpatient interviews and family fixed-line telephone visits. The association between MAFLD and the risk of MACCEs was evaluated through Multivariate Cox regression analyses, Stratified analyses and Kaplan-Meier survival analyses.

Results

Of the 889 subjects, 214 (24.07%) experienced MACCEs. Multivariate Cox regression analysis showed that MAFLD was independently associated with MACCEs (P < 0.001), of which with non-fatal myocardial infarction (P = 0.04), non-fatal stroke (P = 0.047), coronary artery revascularization (P = 0.002), heart failure (P = 0.029), and all-cause mortality (P = 0.021), respectively. The stratified analysis revealed that compared with non-MAFLD (HR=1), DFUs with MAFLD had a 2.64-fold increased risk for MACCEs (P <0.001; P for interaction = 0.001) in peripheral arterial disease (PAD) subgroup. Kaplan-Meier analysis evidenced that the MAFLD group had a higher cumulative incidence of MACCEs (log-rank, all P < 0.05).

Conclusion

MAFLD is a high-risk factor for MACCEs in patients with DFUs. The findings will remind clinicians to pay more attention to MAFLD in patients with DFUs, especially in patients with DFUs combined with PAD as early as possible in clinical practice and adopt timely effective intervention strategies to prevent the occurrence of MACCEs to improve the clinical prognosis in patients with DFUs.

Causal association of nonalcoholic fatty liver disease with 22 extrahepatic cancers: A Mendelian randomization study

AIM

It is unclear whether nonalcoholic fatty liver disease (NAFLD) acts as a direct contributing factor to multiple extrahepatic cancers. We aimed to systematically investigate the causal relationships of NAFLD with extrahepatic cancers.

METHODS

We conducted a two-sample Mendelian randomization analysis to assess the causal effects of NAFLD on 22 extrahepatic cancers. We examined the association of NAFLD with extrahepatic cancers using multiple methods in the largest genome-wide association study meta-analysis to date. We also replicated the analyses and performed two independent sensitivity analysis in the largest genome-wide association study of UK Biobank.

RESULTS

Using the weighted median method, genetically predicted NAFLD was significantly associated with female breast cancer risk (odds ratio [OR] 15.99; 95% confidence interval [CI] 9.58-26.69). Genetically predicted NAFLD is associated with cervical and laryngeal cancers using the inverse variance weighting method, and the ORs were 2.44 (95% CI 1.43-4.14) and 1.94 (95% CI 1.35-2.78), respectively. We observed that patatin-like phospholipase domain-containing protein 3-driven and transmembrane 6 superfamily member 2-driven NAFLD were associated with increased risks of leukemia, lung cancer, and prostate cancers (all with p < 0.05). Furthermore, we confirmed the causal association between NAFLD and breast cancer using five known single-nucleotide polymorphisms of NAFLD and six genome-wide association study-identified variants. The ORs of the weighted median estimator was 10.76 (95% CI 8.27-13.98) and 10.76 (95% CI 8.25-14.04), respectively (p < 0.001).

CONCLUSION

Genetically predicted NAFLD is associated with an increased risk of female breast cancer, as well as cervical, laryngeal, leukemia, lung, and prostate cancers.

CLCF1 inhibits energy expenditure via suppressing brown fat thermogenesis

Brown adipose tissue (BAT) is the main site of nonshivering thermogenesis which plays an important role in thermogenesis and energy metabolism. However, the regulatory factors that inhibit BAT activity remain largely unknown. Here, cardiotrophin-like cytokine factor 1 (CLCF1) is identified as a negative regulator of thermogenesis in BAT. Adenovirus-mediated overexpression of CLCF1 in BAT greatly impairs the thermogenic capacity of BAT and reduces the metabolic rate. Consistently, BAT-specific ablation of CLCF1 enhances the BAT function and energy expenditure under both thermoneutral and cold conditions. Mechanistically, adenylate cyclase 3 (ADCY3) is identified as a downstream target of CLCF1 to mediate its role in regulating thermogenesis. Furthermore, CLCF1 is identified to negatively regulate the PERK-ATF4 signaling axis to modulate the transcriptional activity of ADCY3, which activates the PKA substrate phosphorylation. Moreover, CLCF1 deletion in BAT protects the mice against diet-induced obesity by promoting BAT activation and further attenuating impaired glucose and lipid metabolism. Therefore, our results reveal the essential role of CLCF1 in regulating BAT thermogenesis and suggest that inhibiting CLCF1 signaling might be a potential therapeutic strategy for improving obesity-related metabolic disorders.

Markers of inflammation predict survival in newly diagnosed cirrhosis: a prospective registry study

The inflammatory activity in cirrhosis is often pronounced and related to episodes of decompensation. Systemic markers of inflammation may contain prognostic information, and we investigated their possible correlation with admissions and mortality among patients with newly diagnosed liver cirrhosis. We collected plasma samples from 149 patients with newly diagnosed (within the past 6 months) cirrhosis, and registered deaths and hospital admissions within 180 days. Ninety-two inflammatory markers were quantified and correlated with clinical variables, mortality, and admissions. Prediction models were calculated by logistic regression. We compared the disease courses of our cohort with a validation cohort of 86 patients with cirrhosis. Twenty of 92 markers of inflammation correlated significantly with mortality within 180 days (q-values of 0.00-0.044), whereas we found no significant correlations with liver-related admissions. The logistic regression models yielded AUROCs of 0.73 to 0.79 for mortality and 0.61 to 0.73 for liver-related admissions, based on a variety of modalities (clinical variables, inflammatory markers, clinical scores, or combinations thereof). The models performed moderately well in the validation cohort and were better able to predict mortality than liver-related admissions. In conclusion, markers of inflammation can be used to predict 180-day mortality in patients with newly diagnosed cirrhosis. Prediction models for newly diagnosed cirrhotic patients need further validation before implementation in clinical practice.Trial registration: NCT04422223 (and NCT03443934 for the validation cohort), and Scientific Ethics Committee No.: H-19024348.

Myokines: Crosstalk and Consequences on Liver Physiopathology

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease mainly characterized by the hepatic accumulation of lipid inducing a deregulation of β-oxidation. Its advanced form is non-alcoholic steatohepatitis (NASH), which, in addition to lipid accumulation, induces hepatocellular damage, oxidative stress and fibrosis that can progress to cirrhosis and to its final stage: hepatocellular carcinoma (HCC). To date, no specific therapeutic treatment exists. The implications of organ crosstalk have been highlighted in many metabolic disorders, such as diabetes, metabolic-associated liver diseases and obesity. Skeletal muscle, in addition to its role as a reservoir and consumer of energy and carbohydrate metabolism, is involved in this inter-organs’ communication through different secreted products: myokines, exosomes and enzymes, for example. Interestingly, resistance exercise has been shown to have a beneficial impact on different metabolic pathways, such as lipid oxidation in different organs through their secreted products. In this review, we will mainly focus on myokines and their effects on non-alcoholic fatty liver disease, and their complication: non-alcoholic steatohepatitis and HCC.

Comparative Proteomic Analysis of Liver Tissues and Serum in db/db Mice

Background and Aims: Non-alcoholic fatty liver disease (NAFLD) affects one-quarter of individuals worldwide. Liver biopsy, as the current reliable method for NAFLD evaluation, causes low patient acceptance because of the nature of invasive sampling. Therefore, sensitive non-invasive serum biomarkers are urgently needed. Results: The serum gene ontology (GO) classification and Kyoto encyclopedia of genes and genomes (KEGG) analysis revealed the DEPs enriched in pathways including JAK-STAT and FoxO. GO analysis indicated that serum DEPs were mainly involved in the cellular process, metabolic process, response to stimulus, and biological regulation. Hepatic proteomic KEGG analysis revealed the DEPs were mainly enriched in the PPAR signaling pathway, retinol metabolism, glycine, serine, and threonine metabolism, fatty acid elongation, biosynthesis of unsaturated fatty acids, glutathione metabolism, and steroid hormone biosynthesis. GO analysis revealed that DEPs predominantly participated in cellular, biological regulation, multicellular organismal, localization, signaling, multi-organism, and immune system processes. Protein-protein interaction (PPI) implied diverse clusters of the DEPs. Besides, the paralleled changes of the common upregulated and downregulated DEPs existed in both the liver and serum were validated in the mRNA expression of NRP1, MUP3, SERPINA1E, ALPL, and ALDOB as observed in our proteomic screening. Methods: We conducted hepatic and serum proteomic analysis based on the leptin-receptor-deficient mouse (db/db), a well-established diabetic mouse model with overt obesity and NAFLD. The results show differentially expressed proteins (DEPs) in hepatic and serum proteomic analysis. A parallel reaction monitor (PRM) confirmed the authenticity of the selected DEPs. Conclusion: These results are supposed to offer sensitive non-invasive serum biomarkers for diabetes and NAFLD.