Role of PNPLA3 in Hepatic Stellate Cells and Hepatic Cellular Crosstalk.

AIMS: Since its discovery, the patatin-like phospholipase domain containing 3 (PNPLA3) (rs738409 C>G p.I148M) variant has been studied extensively to unravel its molecular function. Although several studies proved a causal relationship between the PNPLA3 I148M variant and MASLD development and particularly fibrosis, the pathological mechanisms promoting this phenotype have not yet been fully clarified. METHODS: We summarise the latest data regarding the PNPLA3 I148M variant in hepatic stellate cells (HSCs) activation and macrophage biology or the path to inflammation-induced fibrosis. RESULTS: Elegant but contradictory studies have ascribed PNPLA3 a hydrolase or an acyltransferase function. The PNPLA3 I148M results in hepatic lipid accumulation, which predisposes the hepatocyte to lipotoxicity and lipo-apoptosis, producing DAMPs, cytokines and chemokines leading to recruitment and activation of macrophages and HSCs, propagating fibrosis. Recent studies showed that the PNPLA3 I148M variant alters HSCs biology via attenuation of PPARγ, AP-1, LXRα and TGFß activity and signalling. CONCLUSIONS: The advent of refined techniques in isolating HSCs has made PNPLA3's direct role in HSCs for liver fibrosis development more apparent. However, many other mechanisms still need detailed investigations.

Comparison of wild-type and high-risk PNPLA3 variants in a human biomimetic liver microphysiology system for metabolic dysfunction-associated steatotic liver disease precision therapy.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a worldwide health epidemic with a global occurrence of approximately 30%. The pathogenesis of MASLD is a complex, multisystem disorder driven by multiple factors, including genetics, lifestyle, and the environment. Patient heterogeneity presents challenges in developing MASLD therapeutics, creating patient cohorts for clinical trials, and optimizing therapeutic strategies for specific patient cohorts. Implementing pre-clinical experimental models for drug development creates a significant challenge as simple in vitro systems and animal models do not fully recapitulate critical steps in the pathogenesis and the complexity of MASLD progression. To address this, we implemented a precision medicine strategy that couples the use of our liver acinus microphysiology system (LAMPS) constructed with patient-derived primary cells. We investigated the MASLD-associated genetic variant patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs738409 (I148M variant) in primary hepatocytes as it is associated with MASLD progression. We constructed the LAMPS with genotyped wild-type and variant PNPLA3 hepatocytes, together with key non-parenchymal cells, and quantified the reproducibility of the model. We altered media components to mimic blood chemistries, including insulin, glucose, free fatty acids, and immune-activating molecules to reflect normal fasting (NF), early metabolic syndrome (EMS), and late metabolic syndrome (LMS) conditions. Finally, we investigated the response to treatment with resmetirom, an approved drug for metabolic syndrome-associated steatohepatitis (MASH), the progressive form of MASLD. This study, using primary cells, serves as a benchmark for studies using "patient biomimetic twins" constructed with patient induced pluripotent stem cell (iPSC)-derived liver cells using a panel of reproducible metrics. We observed increased steatosis, immune activation, stellate cell activation, and secretion of pro-fibrotic markers in the PNPLA3 GG variant compared to the wild-type CC LAMPS, consistent with the clinical characterization of this variant. We also observed greater resmetirom efficacy in the PNPLA3 wild-type CC LAMPS compared to the GG variant in multiple MASLD metrics, including steatosis, stellate cell activation, and the secretion of pro-fibrotic markers. In conclusion, our study demonstrates the capability of the LAMPS platform for the development of MASLD precision therapeutics, enrichment of patient cohorts for clinical trials, and optimization of therapeutic strategies for patient subgroups with different clinical traits and disease stages.

Dilated cardiomyopathy caused by mutation of the PNPLA2 gene: a case report and literature review.

Deficiency of adipose triglyceride lipase (ATGL) due to mutation in PNPLA2 causes neutral lipid storage disease with myopathy (NLSDM), an autosomal recessive disorder (MIM: #610717). NLSDM patients are mainly affected by progressive myopathy, cardiomyopathy, and hepatomegaly. Cardiac involvement was reported in 40%-50% of NLSDM patients. Patients with cardiac involvement have adult-onset progressive heart failure, mimicking dilated or hypertrophic cardiomyopathy. The clinical characteristics, genotype-phenotype correlation, and prognosis of cardiomyopathy secondary to PNPLA2 mutation are not understood. We reported two male patients carrying a homozygous splicing mutation NM_020376.4 (c.757 + 1G>T) in PNPLA2, presenting with severe dilated cardiomyopathy and mild skeletal muscle involvement. Through the literature review, the ECG and imaging features and the prognosis of 49 previously reported cases of cardiomyopathy caused by the PNPLA2 mutation were summarized. This study suggests that NLSDM should be considered a cause of cardiomyopathy, especially in those with elevated creatine kinase (CK) levels, regardless of whether symptoms such as muscle weakness or atrophy are present.

Two PNPLA2 heterozygous mutations result in neutral lipid storage disease with myopathy: a case report.

BACKGROUND: Neutral Lipid Storage Disease with Myopathy (NLSDM) is a rare lipid metabolism disorder caused by PNPLA2 gene mutations. Clinical manifestations are heterogeneous, and diagnosis is often delayed, usually gaining patients' attention due to the increased risk of cardiomyopathy. CASE PRESENTATION: We herein report a 36-year-old Asian male presenting with progressive limb weakness, muscle atrophy of limbs and trunk, dysarthria, and heart failure. Electromyography indicated myogenic changes, and muscle biopsy results revealed characteristics of lipid storage myopathy. Genetic analysis of PNPLA2 revealed two heterozygous mutations: c.757 + 1G > T (chr11-823588, splice-5) on intron 6 and c.919delG (chr11-823854, p.A307Pfs*13) on exon 7. The patient improved limb strength, and dysarthria disappeared after the Medium Chain Fatty Acids diet. CONCLUSIONS: In conclusion, we report for the first time that the two heterozygous mutations PNPLA2 c.919delG and c.757 + 1G > T together induced NLSDM, which was confirmed by muscle biopsy.

The effect of dulaglutide on glycated hemoglobin is associated with PNPLA3 Ι148Μ gene polymorphism in patients with type 2 diabetes mellitus.

PURPOSE: The evaluation of the effect of dulaglutide on glycated hemoglobin (HbA1c) and non-invasive indices of hepatic steatosis among different genotypes of the PNPLA3 I148M (rs738409) and CETP Taq1B (rs708272) polymorphisms in patients with type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD). METHODS: Relevant data from patients with inadequately controlled T2DM, also displaying NAFLD, administered 1.5 mg dulaglutide weekly for 6 months were retrospectively retrieved. The non-invasive indices, fatty liver index (FLI) and hepatic steatosis index (HSI), were calculated. Genotyping for rs738409 and rs708272 were performed with polymerase chain reaction. RESULTS: Data from 80 patients (39 females), aged 64.4 ± 9.5 years and displaying a baseline BMI of 34.5 ± 5.8 kg/m2, were retrieved at baseline and after 6 months (endpoint) of dulaglutide treatment. Glycated hemoglobin (HbA1c; -0.72 ± 1.10%; p < 0.001), FLI (-5.8 ± 9.8; p < 0.001) and HSI (-1.18 ± 3.51; p = 0.004) significantly decreased after treatment. Lipid profile and liver function tests also improved after treatment. Overall, homozygotes for the reference rs738409 allele (CC) displayed a 2.4-fold decrease (p = 0.002) and heterozygotes (CG) an 1.6-fold decrease (p = 0.013) compared to GG homozygotes after treatment, but the effect was largely limited to female patients. No similar effect was observed in FLI, HSI and other relevant parameters. No association was observed between rs708272 and any of the parameters studied. CONCLUSIONS: rs738409, but not rs708272, was associated with the effect of dulaglutide on HbA1c, but not on presumed hepatic steatosis or other relevant parameters. Sex-specific effects were also noticed.

TM6SF2 E167K variant decreases PNPLA3-mediated PUFA transfer to promote hepatic steatosis and injury in MASLD.

BACKGROUNDS/AIMS: Transmembrane 6 superfamily member 2 (TM6SF2) E167K variant is closely associated with the occurrence and development of metabolic dysfunction-associated steatotic liver disease (MASLD). However, the role and mechanism of TM6SF2 E167K variant during MASLD progression are not yet fully understood. METHODS: The Tm6sf2167K knock-in (KI) mice were subjected to high-fat diet (HFD). Hepatic lipid levels of Tm6sf2167K KI mice were detected by lipidomics analysis. Thin-layer chromatography (TLC) was used to measure the newly synthesized triglyceride (TG) and phosphatidylcholine (PC). RESULTS: The TM6SF2 E167K variant significantly aggravated hepatic steatosis and injury in HFD-induced mice. Decreased polyunsaturated PC level and increased polyunsaturated TG level were found in liver tissue of HFD-induced Tm6sf2167K KI mice. Mechanistic studies demonstrated that the TM6SF2 E167K variant increased the interaction between TM6SF2 and PNPLA3, and impaired PNPLA3-mediated transfer of polyunsaturated fatty acids (PUFAs) from TG to PC. The TM6SF2 E167K variant increased the level of fatty acid-induced malondialdehyde and reactive oxygen species, and decreased fatty acid-downregulated cell membrane fluidity. Additionally, the TM6SF2 E167K variant decreased the level of hepatic PC containing C18:3, and dietary supplementation of PC containing C18:3 significantly attenuated the TM6SF2 E167K-induced hepatic steatosis and injury in HFD-fed mice. CONCLUSION: The TM6SF2 E167K variant could promote its interaction with PNPLA3 and inhibit PNPLA3-mediated transfer of PUFAs from TG to PC, resulting in the hepatic steatosis and injury during MASLD progression. PC containing C18:3 could act as a potential therapeutic supplement for MASLD patients carrying the TM6SF2 E167K variant.

PNPLA3 variation and kidney disease.

Accumulating epidemiological evidence shows that the patatin-like phospholipase domain-containing protein-3 (PNPLA3) rs738409 G allele, which is the most robust genetic variant associated with greater susceptibility to metabolic dysfunction-associated steatotic liver disease (MASLD), is significantly associated with impaired kidney function in both adults and children, regardless of the presence of common renal risk factors, MASLD severity, and other potential confounders. Although some prospective studies have reported a significant association between the PNPLA3 rs738409 G allele and the increased risk of developing chronic kidney disease (CKD), the epidemiological evidence about a possible direct effect of the PNPLA3 rs738409 G allele on the risk of developing CKD is still limited. Experimentally, PNPLA3 is expressed in renal podocytes, pericytes, and proximal tubule cells, thus supporting the notion that the mutant PNPLA3 protein may play a role in developing renal steatosis and fibrosis. However, it cannot be ruled out that a part of the adverse effect of the PNPLA3 rs738409 G allele on kidney function may be driven by a direct impact of this genetic variant on the development and progression of MASLD. It is possible to hypothesize that identifying the PNPLA3 genotype might help identify individuals at higher risk of CKD and those at greater risk of advanced MASLD. In this narrative minireview, we summarize the current epidemiological data about the association between the PNPLA3 rs738409 G allele and the risk of CKD and abnormal albuminuria. We also briefly discuss the putative biological mechanisms underpinning this association and its potential and future clinical implications.

Evidence That Peripheral Leptin Resistance in Omental Adipose Tissue and Liver Correlates with MASLD in Humans.

Leptin regulates lipid metabolism, maximizing insulin sensitivity; however, peripheral leptin resistance is not fully understood, and its contribution to metabolic dysfunction-associated steatotic liver disease (MASLD) is unclear. This study evaluated the contribution of the leptin axis to MASLD in humans. Forty-three participants, mostly female (86.04%), who underwent cholecystectomy were biopsied. Of the participants, 24 were healthy controls, 8 had MASLD, and 11 had metabolic dysfunction-associated steatohepatitis (MASH). Clinical and biochemical data and the gene expression of leptin, leptin receptor (LEPR), suppressor of cytokine signaling 3 (SOCS3), sterol regulatory element-binding transcription factor 1 (SREBF1), stearoyl-CoA desaturase-1 (SCD1), and patatin-like phospholipase domain-containing protein 2 (PNPLA2), were determined from liver and adipose tissue. Higher serum leptin and LEPR levels in the omental adipose tissue (OAT) and liver with MASH were found. In the liver, LEPR was positively correlated with leptin expression in adipose tissue, and SOCS3 was correlated with SREBF1-SCD1. In OAT, SOCS3 was correlated with insulin resistance and transaminase enzymes (p < 0.05 for all. In conclusion, we evidenced the correlation between the peripheral leptin resistance axis in OAT-liver crosstalk and the complications of MASLD in humans.

High patatin like phospholipase domain containing 8 expression as a biomarker for poor prognosis of colorectal cancer.

BACKGROUND: Patatin like phospholipase domain containing 8 (PNPLA8) has been shown to play a significant role in various cancer entities. Previous studies have focused on its roles as an antioxidant and in lipid peroxidation. However, the role of PNPLA8 in colorectal cancer (CRC) progression is unclear. AIM: To explore the prognostic effects of PNPLA8 expression in CRC. METHODS: A retrospective cohort containing 751 consecutive CRC patients was enrolled. PNPLA8 expression in tumor samples was evaluated by immunohistochemistry staining and semi-quantitated with immunoreactive scores. CRC patients were divided into high and low PNPLA8 expression groups based on the cut-off values, which were calculated by X-tile software. The prognostic value of PNPLA8 was identified using univariate and multivariate Cox regression analysis. The overall survival (OS) rates of CRC patients in the study cohort were compared with Kaplan-Meier analysis and Log-rank test. RESULTS: PNPLA8 expression was significantly associated with distant metastases in our cohort (P = 0.048). CRC patients with high PNPLA8 expression indicated poor OS (median OS = 35.3, P = 0.005). CRC patients with a higher PNPLA8 expression at either stage I and II or stage III and IV had statistically significant shorter OS. For patients with left-sided colon and rectal cancer, the survival curves of two PNPLA8-expression groups showed statistically significant differences. Multivariate analysis also confirmed that high PNPLA8 expression was an independent prognostic factor for overall survival (hazard ratio HR = 1.328, 95%CI: 1.016-1.734, P = 0.038). CONCLUSION: PNPLA8 is a novel independent prognostic factor for CRC. These findings suggest that PNPLA8 is a potential target in clinical CRC management.

Prediction of matrilineal specific patatin-like protein governing in-vivo maternal haploid induction in maize using support vector machine and di-peptide composition.

The mutant matrilineal (mtl) gene encoding patatin-like phospholipase activity is involved in in-vivo maternal haploid induction in maize. Doubling of chromosomes in haploids by colchicine treatment leads to complete fixation of inbreds in just one generation compared to 6-7 generations of selfing. Thus, knowledge of patatin-like proteins in other crops assumes great significance for in-vivo haploid induction. So far, no online tool is available that can classify unknown proteins into patatin-like proteins. Here, we aimed to optimize a machine learning-based algorithm to predict the patatin-like phospholipase activity of unknown proteins. Four different kernels [radial basis function (RBF), sigmoid, polynomial, and linear] were used for building support vector machine (SVM) classifiers using six different sequence-based compositional features (AAC, DPC, GDPC, CTDC, CTDT, and GAAC). A total of 1170 protein sequences including both patatin-like (585 sequences) from various monocots, dicots, and microbes; and non-patatin-like proteins (585 sequences) from different subspecies of Zea mays were analyzed. RBF and polynomial kernels were quite promising in the prediction of patatin-like proteins. Among six sequence-based compositional features, di-peptide composition attained > 90% prediction accuracies using RBF and polynomial kernels. Using mutual information, most explaining dipeptides that contributed the highest to the prediction process were identified. The knowledge generated in this study can be utilized in other crops prior to the initiation of any experiment. The developed SVM model opened a new paradigm for scientists working in in-vivo haploid induction in commercial crops. This is the first report of machine learning of the identification of proteins with patatin-like activity.

What are the common downstream molecular events between alcoholic and nonalcoholic fatty liver?

Liver fat storage, also called hepatic steatosis, is increasingly common and represents a very frequent diagnosis in the medical field. Excess fat is not without consequences. In fact, hepatic steatosis contributes to the progression toward liver fibrosis. There are two main types of fatty liver disease, alcoholic fatty liver disease (AFLD) and nonalcoholic fatty liver disease (NAFLD). Although AFLD and NAFLD are similar in their initial morphological features, both conditions involve the same evolutive forms. Moreover, there are various common mechanisms underlying both diseases, including alcoholic liver disease and NAFLD, which are commonalities. In this Review, the authors explore similar downstream signaling events involved in the onset and progression of the two entities but not completely different entities, predominantly focusing on the gut microbiome. Downstream molecular events, such as the roles of sirtuins, cytokeratins, adipokines and others, should be considered. Finally, to complete the feature, some new tendencies in the therapeutic approach are presented.

Neutral lipid storage disease with myopathy: clinicopathological and genetic features of nine Iranian patients.

The rare disorder known as Neutral Lipid Storage Disease with Myopathy presents with a variety of clinical manifestations, including myopathy, cardiac dysfunction, and other organ complications. Early diagnosis is crucial due to the increased risk of cardiomyopathy. We describe the clinical, histopathological, muscle imaging, and genetic findings of nine neutral lipid storage myopathy patients. Proximal weakness and asymmetric involvement may suggest lipid storage myopathy. While skeletal muscle weakness was the main manifestation in our patients, one case presented only with hyperCKemia. Additionally, three patients had fertility issues, two suffered from diabetes mellitus, two had cardiomyopathy, and one had a history of hypothyroidism. Muscle histopathology revealed lipid depositions and rimmed vacuoles, prompting peripheral blood smears to detect Jordan Anomalies. All muscle biopsies and peripheral blood smear showed lipid droplets, rimmed vacuoles, and Jordan anomaly. Identifying PNPLA2 gene mutations is important for diagnosing neutral lipid storage myopathy; our cases showed some novel mutations. This study highlights the importance of early diagnosis and comprehensive evaluation in managing neutral lipid storage myopathy cases.

LOX1- and PLP1-dependent transcriptional reprogramming is essential for injury-induced conidiophore development in a filamentous fungus.

IMPORTANCE: In addition to being considered a biocontrol agent, the fungus Trichoderma atroviride is a relevant model for studying mechanisms of response to injury conserved in plants and animals that opens a new landscape in relation to regeneration and cell differentiation mechanisms. Here, we reveal the co-functionality of a lipoxygenase and a patatin-like phospholipase co-expressed in response to wounding in fungi. This pair of enzymes produces oxidized lipids that can function as signaling molecules or oxidative stress signals that, in ascomycetes, induce asexual development. Furthermore, we determined that both genes participate in the regulation of the synthesis of 13-HODE and the establishment of the physiological responses necessary for the formation of reproductive aerial mycelium ultimately leading to asexual development. Our results suggest an injury-induced pathway to produce oxylipins and uncovered physiological mechanisms regulated by LOX1 and PLP1 to induce conidiation, opening new hypotheses for the novo regeneration mechanisms of filamentous fungi.

The PNPLA3 I148M variant increases ketogenesis and decreases hepatic de novo lipogenesis and mitochondrial function in humans.

The PNPLA3 I148M variant is the major genetic risk factor for all stages of fatty liver disease, but the underlying pathophysiology remains unclear. We studied the effect of this variant on hepatic metabolism in homozygous carriers and non-carriers under multiple physiological conditions with state-of-the-art stable isotope techniques. After an overnight fast, carriers had higher plasma ß-hydroxybutyrate concentrations and lower hepatic de novo lipogenesis (DNL) compared to non-carriers. After a mixed meal, fatty acids were channeled toward ketogenesis in carriers, which was associated with an increase in hepatic mitochondrial redox state. During a ketogenic diet, carriers manifested increased rates of intrahepatic lipolysis, increased plasma ß-hydroxybutyrate concentrations, and decreased rates of hepatic mitochondrial citrate synthase flux. These studies demonstrate that homozygous PNPLA3 I148M carriers have hepatic mitochondrial dysfunction leading to reduced DNL and channeling of carbons to ketogenesis. These findings have implications for understanding why the PNPLA3 variant predisposes to progressive liver disease.

A patatin-like phospholipase is important for mitochondrial function in malaria parasites.

Plasmodium parasites rely on a functional electron transport chain (ETC) within their mitochondrion for proliferation, and compounds targeting mitochondrial functions are validated antimalarials. Here, we localize Plasmodium falciparum patatin-like phospholipase 2 (PfPNPLA2, PF3D7_1358000) to the mitochondrion and reveal that disruption of the PfPNPLA2 gene impairs asexual replication. PfPNPLA2-null parasites are hypersensitive to proguanil and inhibitors of the mitochondrial ETC, including atovaquone. In addition, PfPNPLA2-deficient parasites show reduced mitochondrial respiration and reduced mitochondrial membrane potential, indicating that disruption of PfPNPLA2 leads to a defect in the parasite ETC. Lipidomic analysis of the mitochondrial phospholipid cardiolipin (CL) reveals that loss of PfPNPLA2 is associated with a moderate shift toward shorter-chained and more saturated CL species, implying a contribution of PfPNPLA2 to CL remodeling. PfPNPLA2-deficient parasites display profound defects in gametocytogenesis, underlining the importance of a functional mitochondrial ETC during both the asexual and sexual development of the parasite. IMPORTANCE For their proliferation within red blood cells, malaria parasites depend on a functional electron transport chain (ETC) within their mitochondrion, which is the target of several antimalarial drugs. Here, we have used gene disruption to identify a patatin-like phospholipase, PfPNPLA2, as important for parasite replication and mitochondrial function in Plasmodium falciparum. Parasites lacking PfPNPLA2 show defects in their ETC and become hypersensitive to mitochondrion-targeting drugs. Furthermore, PfPNPLA2-deficient parasites show differences in the composition of their cardiolipins, a unique class of phospholipids with key roles in mitochondrial functions. Finally, we demonstrate that parasites devoid of PfPNPLA2 have a defect in gametocyte maturation, underlining the importance of a functional ETC for parasite transmission to the mosquito vector.

A study of genetic variants, genetic risk score and DNA methylation of PNPLA3 and TM6SF2 in alcohol liver cirrhosis.

BACKGROUND: Genetic and epigenetic factors are associated with the development of alcohol-associated liver disease (AALD). The single nucleotide polymorphisms (SNPs), rs738409 in Patatin-like phospholipase domain-containing protein (PNPLA3) and rs58542926 in Transmembrane 6 Superfamily Member 2 (TM6SF2) are strongly associated with AALD in different global populations, Hence, we analyzed the genetic risk score for these variants and deoxyribonucleic acid (DNA) methylation levels of the PNPLA3 and TM6SF2 genes among cases (alcohol liver cirrhosis) and controls (heavy drinkers without cirrhosis). METHOD: We studied patients with alcohol use disorder (AUD) with cirrhosis (AUD-C + ve, n = 136) and without cirrhosis (AUD-C-ve, n = 107) drawn from the clinical services of St. John's Medical College Hospital (SJMCH) (Gastroenterology and Psychiatry) and Centre for Addiction Medicine (CAM), National Institute of Mental Health and Neurosciences, (NIMHANS). Genotype data was generated for rs738409 (PNPLA3) and rs58542926 (TM6SF2) and used to calculate unweighted genetic risk score (uGRS) and weighted genetic risk scores (wGRS). DNA methylation levels were estimated by pyrosequencing at PNPLA3 and TM6SF2 loci. RESULTS: Overall we observed a significantly higher genetic risk score (weighted genetic risk score, wGRS) in individuals with alcohol use disorder compared to control population (p = < 0.01). Further, uGRS and wGRS were associated with the diagnosis of cirrhosis, even after correcting for age of onset, quantity and frequency of drinking. We also found hypomethylation at CpG2 of TM6SF2 gene in AUD-C + ve compared to AUD-C-ve (P = 0.02). CONCLUSION: We found that a genetic risk score based on SNPs in the PNPLA3 and TM6SF2 genes was significantly associated with cirrhosis in patients with AUD, suggesting a potential utility in identifying patients at risk and providing pre-emptive interventions. These may include interventions that aim to alter DNA methylation, which may be one of the mechanisms through which elevated genetic risk may influence the development of cirrhosis.

Analysis of genetic factors associated with fatty liver disease-related hepatocellular carcinoma.

AIM: Single-nucleotide polymorphisms (SNPs) in PNPLA3 and hydroxysteroid 17-beta dehydrogenase 13 (HSD17B13) genes are associated with fatty liver disease (FLD) progression and carcinogenesis. In the present study, we evaluated the characteristics of Japanese FLD patients according to HSD17B13 polymorphisms. METHODS: We enrolled 402 patients who were clinically and pathologically diagnosed with FLD (alcoholic: 63 cases, nonalcoholic: 339 cases) at our hospital in 1990-2018 (228 males; median age: 54.9 [14.6-83.6] years). FLD patients with HSD17B13 A/A (212 cases) and others (A/AA or AA/AA; 190 cases) were compared. RESULTS: Compared to patients with HSD17B13 A/A and others, those with the A/A genotype showed increased incidence of hepatocellular carcinoma (HCC) (A/A vs. others; 18.4% vs. 9.5%, p = 0.01), cardiovascular diseases (14.2% vs. 4.2%, p < 0.01), and hypertension (56.6% vs. 47.4%, p = 0.06). In patients without A/A, the HCC incidence was significantly reduced in those with alcohol-related FLD, fibrosis-4 index <2.67, and the PNPLA3 CC genotype; however, there was no significant difference in nonalcoholic-FLD. Patients without HSD17B13 A/A showed severe steatosis (77% vs. 88.6%, p < 0.01). New HCC developed in 11 cases and the 5-year incidence rate of HCC was 3.3% in patients with both PNPLA3 GG/GC and HSD17B13 A/A, which was significantly higher than the rate for those with other SNP profiles (0.6%, p = 0.03). CONCLUSIONS: Inhibiting HSD17B13 activity may prevent HCC development, particularly in alcohol-related FLD and low-risk patients. Therefore, combinations of SNPs and other risk factors can be used for screening FLD-HCC.

High producer variant of lipoprotein lipase may protect from hepatocellular carcinoma in alcohol-associated cirrhosis.

Background & Aims: Progression of alcohol-associated liver disease (ALD) is driven by genetic predisposition. The rs13702 variant in the lipoprotein lipase (LPL) gene is linked to non-alcoholic fatty liver disease. We aimed at clarifying its role in ALD. Methods: Patients with alcohol-associated cirrhosis, with (n = 385) and without hepatocellular carcinoma (HCC) (n = 656), with HCC attributable to viral hepatitis C (n = 280), controls with alcohol abuse without liver damage (n = 366), and healthy controls (n = 277) were genotyped regarding the LPL rs13702 polymorphism. Furthermore, the UK Biobank cohort was analysed. LPL expression was investigated in human liver specimens and in liver cell lines. Results: Frequency of the LPL rs13702 CC genotype was lower in ALD with HCC in comparison to ALD without HCC both in the initial (3.9% vs. 9.3%) and the validation cohort (4.7% vs. 9.5%; p <0.05 each) and compared with patients with viral HCC (11.4%), alcohol misuse without cirrhosis (8.7%), or healthy controls (9.0%). This protective effect (odds ratio [OR] = 0.5) was confirmed in multivariate analysis including age (OR = 1.1/year), male sex (OR = 3.0), diabetes (OR = 1.8), and carriage of the PNPLA3 I148M risk variant (OR = 2.0). In the UK Biobank cohort, the LPL rs13702 C allele was replicated as a risk factor for HCC. Liver expression of LPL mRNA was dependent on LPL rs13702 genotype and significantly higher in patients with ALD cirrhosis compared with controls and alcohol-associated HCC. Although hepatocyte cell lines showed negligible LPL protein expression, hepatic stellate cells and liver sinusoidal endothelial cells expressed LPL. Conclusions: LPL is upregulated in the liver of patients with alcohol-associated cirrhosis. The LPL rs13702 high producer variant confers protection against HCC in ALD, which might help to stratify people for HCC risk. Impact and implications: Hepatocellular carcinoma is a severe complication of liver cirrhosis influenced by genetic predisposition. We found that a genetic variant in the gene encoding lipoprotein lipase reduces the risk for hepatocellular carcinoma in alcohol-associated cirrhosis. This genetic variation may directly affect the liver, because, unlike in healthy adult liver, lipoprotein lipase is produced from liver cells in alcohol-associated cirrhosis.

Expression and function of patatin-like phospholipase domain-containing 2 in cleft palate induced by retinoic acid.

Cleft palate is a common maxillofacial congenital malformation, and its mechanism still has not been fully illustrated. Recently, lipid metabolic defects have been observed in cleft palate. Patatin-like phospholipase domain-containing 2 (Pnpla2) is an important lipolytic gene. However, its effect on the formation of cleft palate remains unknown. In this research, we explored the expression of Pnpla2 in the palatal shelves of control mice. We also studied mice with cleft palates induced by retinoic acid and its effect on the embryonic palatal mesenchyme (EPM) cells phenotype. We found that Pnpla2 was expressed in the palatal shelves of both the cleft palate and control mice. Pnpla2 expression was lower in cleft palate mice than in the control mice. Experiments with EPM cells showed that knockdown of Pnpla2 inhibited cell proliferation and migration. In conclusion, Pnpla2 is linked to palatal development. We have indicated that low expression of Pnpla2 affects palatogenesis by inhibiting the proliferation and migration of EPM cells.