bims-faldev 2024-07-14 papers

bims-faldev

Biomed News

on Fatty liver disease and extracellular vesicles

Issue of 2024–07–14
eight papers selected by
Stepheny Carneiro de Campos Zani, Universidade Estadual de Campinas

Safety and efficacy of resmetirom in the treatment of patients with non-alcoholic steatohepatitis and liver fibrosis: a systematic review and meta-analysis.
Integrator complex subunit 6 promotes hepatocellular steatosis via β-catenin-PPARγ axis.
A PNPLA3-Deficient iPSC-Derived Hepatocyte Screen Identifies Pathways to Potentially Reduce Steatosis in Metabolic Dysfunction-Associated Fatty Liver Disease.
Exploring Fibrosis Pathophysiology in Lean and Obese Metabolic-Associated Fatty Liver Disease: An In-Depth Comparison.
Induction of steatosis in primary human hepatocytes recapitulates key pathophysiological aspects of metabolic dysfunction-associated steatotic liver disease.
Hepatocyte-derived extracellular vesicles regulate liver regeneration after partial hepatectomy.
Discovery of Novel Peptide Antagonists Targeting GPR55 for Liver Inflammation and Fibrosis.
Adipose Tissue Dysfunction and the Role of Adipocyte-Derived Extracellular Vesicles in Obesity and Metabolic Syndrome.

Ann Med Surg (Lond). 2024 Jul;86(7): 4130-4138

Safety and efficacy of resmetirom in the treatment of patients with non-alcoholic steatohepatitis and liver fibrosis: a systematic review and meta-analysis.

Adarsh Raja, Raja Subhash Sagar, Sadia Saeed, Amna Zia Ul Haq, Owais Khan, Parshant Dileep Bhimani, Sandesh Raja, Fnu Deepak, Muhammad Ahmed, Muhammad Ashir Shafique, Muhammad Saqlain Mustafa, Muhammad Sohaib Asghar, Varsha Sharma.

   Introduction: Non-alcoholic fatty liver disease (NAFLD), spanning from non-alcoholic steatohepatitis (NASH) to liver fibrosis, poses a global health challenge amid rising obesity and metabolic syndrome rates. Effective pharmacological treatments for NASH and liver fibrosis are limited.
Objective: This study systematically reviews and meta-analyzes the safety and efficacy of resmetirom, a selective thyroid hormone receptor-β agonist, in NASH and liver fibrosis treatment. By analyzing data from clinical trials, we aim to offer evidence-based recommendations for resmetirom's use in managing these conditions and identify avenues for future research.
Methods: Electronic databases (PubMed, Scopus, Science Direct, Google Scholar, ClinicalTrials.gov, and Cochrane CENTRAL) were systematically searched, supplemented by manual screening of relevant sources. Only English-language randomized controlled trials were included. Data extraction, risk of bias assessment, pooled analyses, and meta-regression were performed.
Results: Three randomized controlled trials involving 2231 participants were analyzed. Resmetirom demonstrated significant reductions in hepatic fat fraction [standardized mean difference (SMD) -4.61, 95% CI -6.77 to -2.44, P < 0.0001], NASH resolution without worsening fibrosis [risk ratio (RR) 2.51, 95% CI 1.74-3.64, P = 0.00001), and liver fibrosis improvement (RR 2.31, 95% CI 1.20-4.44, P = 0.01). Secondary outcomes showed significant improvements in lipid profiles, liver enzymes, and NASH biomarkers with resmetirom treatment. Meta-regression revealed associations between covariates and primary outcomes.
Conclusion: Resmetirom exhibits promising efficacy in reducing hepatic fat, improving NASH resolution, and ameliorating liver fibrosis with a favorable safety profile. Further research is warranted to validate findings and optimize therapeutic strategies for NASH and liver fibrosis management.

Keywords:  liver fibrosis; non-alcoholic steatohepatitis (NASH); placebo; resmetirom; thyroid hormone receptor-beta agonist

DOI:  https://doi.org/10.1097/MS9.0000000000002195
Biochim Biophys Acta Mol Cell Biol Lipids. 2024 Jul 07. pii: S1388-1981(24)00082-9. [Epub ahead of print] 159532

Integrator complex subunit 6 promotes hepatocellular steatosis via β-catenin-PPARγ axis.

Minami Shiozaki, Keishi Kanno, Sayaka Yonezawa, Yuichiro Otani, Yuya Shigenobu, Daisuke Haratake, Eisuke Murakami, Shiro Oka, Masanori Ito.

  Hepatic adipogenesis has common mechanisms with adipocyte differentiation such as PPARγ involvement and the induction of adipose tissue-specific molecules. A previous report demonstrated that integrator complex subunit 6 (INTS6) is required for adipocyte differentiation. This study aimed to investigate INTS6 expression and its role in hepatic steatosis progression. The expression of INTS6 and PPARγ was examined in the liver of a mouse model of steatohepatitis and in paired liver biopsy samples from 11 patients with severe obesity and histologically proven metabolic dysfunction associated steatohepatitis (MASH) before and one year after bariatric surgery. To induce hepatocellular steatosis in vitro, an immortalized human hepatocyte cell line Hc3716 was treated with free fatty acids. In the steatohepatitis mouse model, we observed hepatic induction of INTS6, PPARγ, and adipocyte-specific genes. In contrast, β-catenin which negatively regulates PPARγ was reduced. Biopsied human livers demonstrated a strong positive correlation (r2 = 0.8755) between INTS6 and PPARγ mRNA levels. After bariatric surgery, gene expressions of PPARγ, FABP4, and CD36 were mostly downregulated. In our in vitro experiments, we observed a concentration-dependent increase in Oil Red O staining in Hc3716 cells after treatment with the free fatty acids. Alongside this change, the expression of INTS6, PPARγ, and adipocyte-specific genes was induced. INTS6 knockdown using siRNA significantly suppressed cellular lipid accumulation together with induction of β-catenin and PPARγ downregulation. Collectively, INTS6 expression closely correlates with PPARγ. INTS6 suppression significantly reduced hepatocyte steatosis via β-catenin-PPARγ axis, indicating that INTS6 could be a novel therapeutic target for treating MASH.

Keywords:  Adipogenesis; Integrator complex subunit 6; Lipid metabolism; Metabolic dysfunction-associated steatohepatitis; Metabolic dysfunction-associated steatotic liver disease

DOI:  https://doi.org/10.1016/j.bbalip.2024.159532
Int J Mol Sci. 2024 Jul 02. pii: 7277. [Epub ahead of print]25(13):

A PNPLA3-Deficient iPSC-Derived Hepatocyte Screen Identifies Pathways to Potentially Reduce Steatosis in Metabolic Dysfunction-Associated Fatty Liver Disease.

Caren Doueiry, Christiana S Kappler, Carla Martinez-Morant, Stephen A Duncan.

  The incidence of nonalcoholic fatty liver disease (NAFLD), or metabolic dysfunction-associated fatty liver disease (MAFLD), is increasing in adults and children. Unfortunately, effective pharmacological treatments remain unavailable. Single nucleotide polymorphisms (SNPs) in the patatin-like phospholipase domain-containing protein (PNPLA3 I148M) have the most significant genetic association with the disease at all stages of its progression. A roadblock to identifying potential treatments for PNPLA3-induced NAFLD is the lack of a human cell platform that recapitulates the PNPLA3 I148M-mediated onset of lipid accumulation. Hepatocyte-like cells were generated from PNPLA3-/- and PNPLA3I148M/M-induced pluripotent stem cells (iPSCs). Lipid levels were measured by staining with BODIPY 493/503 and were found to increase in PNPLA3 variant iPSC-derived hepatocytes. A small-molecule screen identified multiple compounds that target Src/PI3K/Akt signaling and could eradicate lipid accumulation in these cells. We found that drugs currently in clinical trials for cancer treatment that target the same pathways also reduced lipid accumulation in PNPLA3 variant cells.

Keywords:  MAFLD; NAFLD; drug discovery; small molecules; steatosis; stem cells

DOI:  https://doi.org/10.3390/ijms25137277
Int J Mol Sci. 2024 Jul 05. pii: 7405. [Epub ahead of print]25(13):

Exploring Fibrosis Pathophysiology in Lean and Obese Metabolic-Associated Fatty Liver Disease: An In-Depth Comparison.

Milena Vesković, Milka Pejović, Nikola Šutulović, Dragan Hrnčić, Aleksandra Rašić-Marković, Olivera Stanojlović, Dušan Mladenović.

  While obesity-related nonalcoholic fatty liver disease (NAFLD) is linked with metabolic dysfunctions such as insulin resistance and adipose tissue inflammation, lean NAFLD more often progresses to liver fibrosis even in the absence of metabolic syndrome. This review aims to summarize the current knowledge regarding the mechanisms of liver fibrosis in lean NAFLD. The most commonly used lean NAFLD models include a methionine/choline-deficient (MCD) diet, a high-fat diet with carbon tetrachloride (CCl4), and a high-fructose and high-cholesterol diet. The major pro-fibrogenic mechanisms in lean NAFLD models include increased activation of the extracellular signal-regulated kinase (ERK) pathway, elevated expression of α-smooth muscle actin (α-SMA), collagen type I, and TGF-β, and modulation of fibrogenic markers such as tenascin-X and metalloproteinase inhibitors. Additionally, activation of macrophage signaling pathways promoting hepatic stellate cell (HSC) activation further contributes to fibrosis development. Animal models cannot cover all clinical features that are evident in patients with lean or obese NAFLD, implicating the need for novel models, as well as for deeper comparisons of clinical and experimental studies. Having in mind the prevalence of fibrosis in lean NAFLD patients, by addressing specific pathways, clinical studies can reveal new targeted therapies along with novel biomarkers for early detection and enhancement of clinical management for lean NAFLD patients.

Keywords:  CCl4; MCD diet; animal models; fibrosis; lean NAFLD

DOI:  https://doi.org/10.3390/ijms25137405
J Hepatol. 2024 Jul 06. pii: S0168-8278(24)02347-X. [Epub ahead of print]

Induction of steatosis in primary human hepatocytes recapitulates key pathophysiological aspects of metabolic dysfunction-associated steatotic liver disease.

Yun Kwon, Pascal Gottmann, Surui Wang, Joel Tissink, Karsten Motzler, Revathi Sekar, Wiebke Albrecht, Cristina Cadenas, Jan G Hengstler, Annette Schürmann, Anja Zeigerer.

   BACKGROUND & AIMS: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common cause of chronic liver disease. Its limited treatment options warrant novel pre-clinical models for target selection and drug validation. We have established and extensively characterized a primary human steatotic hepatocyte in vitro model system that could guide treatment strategies for MASLD.
METHODS: Cryopreserved primary human hepatocytes from five donors varying in sex and ethnicity were cultured with free fatty acids (FFA) in 3D collagen sandwich for 7 days and the development of MASLD was followed by assessing classical hepatocellular functions. As proof of concept, the effects of the drug Firsocostat (GS-0976) on in vitro MASLD phenotypes were evaluated.
RESULTS: Incubation with FFA induced steatosis, insulin resistance, mitochondrial dysfunction, inflammation, and alterations in prominent human gene signatures similar to patients with MASLD, indicating the recapitulation of human MASLD in this system. As the application of Firsocostat rescued clinically observed fatty liver disease pathologies, it highlights the ability of the in vitro system to test drug efficacy and potentially characterize their mode of action.
CONCLUSIONS: Altogether, our human MASLD in vitro model system could guide the development and validation of novel targets and drugs for the treatment of MASLD.
IMPACT AND IMPLICATIONS: Due to low drug efficacy and high toxicity, a clinical treatment option for MASLD is limited. To facilitate earlier stop-go decisions in drug development, we have established a primary human steatotic hepatocyte in vitro model. As the model recapitulates clinically relevant MASLD characteristics at high phenotypic resolution, it can serve as a pre-screening platform and guide target identification and validation in MASLD therapy.

Keywords:  MASH; MASLD; NAFLD; NASH; drug discovery and validation; primary human hepatocytes

DOI:  https://doi.org/10.1016/j.jhep.2024.06.040
bioRxiv. 2024 Jun 26. pii: 2024.06.25.600679. [Epub ahead of print]

Hepatocyte-derived extracellular vesicles regulate liver regeneration after partial hepatectomy.

Mina McGinn, Christopher Rabender, Ross Mikkelsen, Vasily Yakovlev.

While significant progress has been made in understanding different aspects of liver regeneration, the molecular mechanisms responsible for the initiation and termination of cell proliferation in the liver after massive loss or injury of liver tissue remain unknown. The loss of liver mass affects tissue-specific mitogenic inhibitors in the blood, which in turn regulate the proliferation of remaining hepatocytes and liver regeneration. Although well described in a number of publications, which inhibitory substances or "sensor molecules" control the regeneration mechanisms to properly maintain liver size remain unknown. Extracellular vesicles (EVs) are nano-sized, membrane-limited structures secreted by cells into the extracellular space. Their proposed role is stable intercellular carriers of proteins and RNAs, mostly micro-RNA, from secreted to recipient cells. Taken up by the recipient cells, EVs can significantly modulate their biological functions. In the present study, using in vivo and in vitro models, we demonstrate that hepatocyte proliferation and liver regeneration are regulated by EVs secreted by hepatocytes into the bloodstream. This regulation is carried out through a negative feedback mechanism, which explains the very precise regeneration of liver tissue after massive damage. We also demonstrate that an essential component of this mechanism is RNA carried by hepatocyte-derived EVs. These findings open up a new and unexplored area of biology regarding the mechanisms involved in the homeostasis regulation of various constantly renewing tissues by maintaining the optimal size and correct ratio between differentiating and proliferating cells.

DOI: https://doi.org/10.1101/2024.06.25.600679
J Med Chem. 2024 Jul 11.

Discovery of Novel Peptide Antagonists Targeting GPR55 for Liver Inflammation and Fibrosis.

Zihan Shi, Xianyan Liu, Shuohan Wu, Nazi Song, Qinglin Tang, Haonan Li, Suijia Luo, Albert S C Chan, Xiaoqing Cai, Han Liu, Xianxing Jiang.

Liver fibrosis is a condition characterized by aberrant proliferation of connective tissue in the liver resulting from diverse etiological factors. G protein-coupled receptor GPR55 has recently been identified as a regulator of liver diseases. Herein, we report the discovery of a cyclic peptide P1-1 that antagonizes GPR55 and suppresses collagen secretion in hepatic stellate cells. The alanine scanning and docking study was carried out to predict the binding mode and allowed for further structural optimization of peptide antagonists for GPR55. The subsequent in vivo study demonstrated that P1-1 ameliorates CCl4-induce and MCD-diet-induce acute liver inflammation and fibrosis. Further study indicates that P1-1 reduces reactive oxygen species (ROS) production, attenuates ER stress, and inhibits mitochondria-associated hepatocyte apoptosis. In this work, we provided the first successful example of antagonizing GPR55 for liver inflammation and fibrosis, which validates GPR55 as a promising target for the treatment of liver fibrosis and affords a high-potent GPR55 antagonist P1-1 as a potential therapeutic candidate.

DOI: https://doi.org/10.1021/acs.jmedchem.4c00834
J Endocr Soc. 2024 Jul 01. 8(8): bvae126

Adipose Tissue Dysfunction and the Role of Adipocyte-Derived Extracellular Vesicles in Obesity and Metabolic Syndrome.

Alejandra Sandoval-Bórquez, Pablo Carrión, María Paz Hernández, Jorge A Pérez, Alejandra Tapia-Castillo, Andrea Vecchiola, Carlos E Fardella, Cristian A Carvajal.

  Obesity is a major public health issue that is associated with metabolic diseases including diabetes mellitus type 2 and metabolic syndrome. This pathology leads to detrimental cardiovascular health and secondary effects, such as lipotoxicity, inflammation, and oxidative stress. Recently, extracellular vesicles (EVs) have been highlighted as novel players participating in human physiology and pathophysiology. In obesity, adipose tissue is related to the active shedding of adipocyte-derived extracellular vesicles (AdEVs). The current review explores and highlights the role of AdEVs and their cargo in obesity and metabolic syndrome. AdEVs are proposed to play an important role in obesity and its comorbidities. AdEVs are biological nanoparticles mainly shed by visceral and subcutaneous adipose tissue, acting in physiological and pathophysiological conditions, and also carrying different cargo biomolecules, such as RNA, microRNA (miRNA), proteins, and lipids, among others. RNA and miRNA have local and systemic effects affecting gene expression in target cell types via paracrine and endocrine actions. State of the art analyses identified some miRNAs, such as miR-222, miR-23b, miR-4429, miR-148b, and miR-4269, that could potentially affect cell pathways involved in obesity-related comorbidities, such as chronic inflammation and fibrosis. Similarly, AdEVs-proteins (RBP4, perilipin-A, FABP, mimecan, TGFBI) and AdEVs-lipids (sphingolipids) have been linked to the obesity pathophysiology. The current knowledge about AdEVs along with further research would support and reveal novel pathways, potential biomarkers, and therapeutic options in obesity.

Keywords:  adipocyte-derived extracellular vesicles (AdEVs); metabolic syndrome; obesity

DOI:  https://doi.org/10.1210/jendso/bvae126