Platelet TGF-β1 deficiency decreases liver fibrosis in a mouse model of liver injury

Early Postoperative Increase in Transforming Growth Factor Beta-1 Predicts Microvascular Flap Loss in Reconstructive Surgery: A Prospective Cohort Study

Background and Objectives: Microvascular flap surgery is a widely used reconstructive technique for the repair of various defects. Biomarkers have become an essential tool for monitoring flap viability, early detection of complications, and prediction of surgical outcomes. Studies focusing on immunomodulatory cytokines in the early prediction of microvascular flap complications are lacking. We aimed to investigate the predictive value of postoperative changes in transforming growth factor beta-1 (TGF-β1) for microvascular flap complications. Materials and Methods: This prospective observational study comprised 44 adults scheduled for elective microvascular flap surgery. Preoperative blood samples for analysis were obtained before surgery, prior to the administration of intravenous fluids. Postoperative blood draws were collected after surgery, before leaving the operating room. Preoperative and postoperative serum concentrations of TGF-β1, as well as preoperative plasma albumin, total protein, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, full blood count, albumin, interleukin-6, C-reactive protein, and fibrinogen, were determined. Results: Postoperative changes in TGF-β1 were higher in cases with flap loss compared to patients with healthy recovery or patients with minor flap complications (0.403 log10 of ng/mL [0.024-0.782] vs. 0.157 [0.029-0.285] vs. -0.089 [-0.233-0.056], p = 0.002). Increased postoperative TGF-β1 was positively linked to preoperative C-reactive protein (p = 0.021), fibrinogen (p = 0.020), hematocrit (p = 0.039), and hemoglobin (p = 0.009). Conclusions: The postoperative increase in circulating TGF-β1 was associated with microvascular flap complications. Assessment of the postoperative changes in circulating TGF-β1 may be valuable for the early postoperative prediction of true flap loss.

Protective effects of Scutellaria barbata against hepatocyte apoptosis during hepatic fibrosis progression

Scutellaria barbata is a medicinal plant with anti-inflammatory, antioxidant, and antitumor properties. Limited studies exist on the link between S. barbata and liver fibrosis. The focus of this study is to examine the impact of S. barbata-containing serum on rat hepatocytes undergoing hepatic fibrosis. Molecular mechanisms underlying the observed effects are sought to be predicted. Transforming growth factor β1 (TGF-β1)-treated hepatic stellate cells (HSCs) supernatant was utilized to produce hepatic fibrosis-like conditions in hepatocytes BRL-3A cultured in vitro. S. barbata-containing serum was used as an intervention, with various dosage groups and a positive drug group (N-acetylcysteine). Cell proliferation, mitochondrial membrane potential (MMP), apoptosis, and expression of apoptosis-related proteins and genes were assessed through various assays and techniques. Bioinformatics analysis was employed to predict target genes and signaling pathways affected by S. barbata. Chemical components of S. barbata in the serum were detected by ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-QE-MS) was used to identify. Cellular experiments demonstrated that S. barbata-containing serum restored cell proliferation and reduced apoptotic activity induced by the fibrosis model, with a significant downregulation of apoptosis-related proteins (cleaved-Caspase-3, Bax), a substantial upregulation of the anti-apoptotic protein BCL-2, and a substantial elevation in the level of cellular MMP. Bioinformatics analysis highlighted the involvement of S. barbata in hepatocyte apoptosis during liver fibrosis, possibly through pathways like PI3K-Akt. UHPLC-QE-MS identified 29 chemical components of S. barbata in the bloodstream, suggesting their role in anti-hepatic fibrosis effects. S. barbata was found to effectively inhibit hepatocyte apoptosis during hepatic fibrosis.

Ergothioneine Ameliorates Liver Fibrosis by Inhibiting Glycerophospholipids Metabolism and TGF-β/Smads Signaling Pathway: Based on Metabonomics and Network Pharmacology

Ergothioneine (EGT) is a diet-derived natural sulfur-containing amino acid that exhibits strong anti-oxidant and anti-inflammation activities. Oxidative stress and chronic inflammatory injury are predominant pro-fibrogenic factors. Therefore, EGT may have therapeutic potential against liver fibrosis; however, its underlying mechanism is incompletely understood. This study aimed at investigating the protective effects of EGT on liver fibrosis based on metabonomics and network pharmacology. A mouse model of liver fibrosis was established by intraperitoneal injection with 40% CCl4 solution (2 mL/kg, twice a week) and intragastric administration with EGT (5, 10 mg/kg/d) for six weeks. Results showed that EGT improved liver function by reducing serum levels of ALT (alanine aminotransferase), AST (aspartate aminotransferase), and TBIL (total bilirubin), and alleviated liver fibrosis by reducing LN (laminin) and HyP (hydroxyproline) levels, decreasing expressions of α-SMA (α-smooth muscle actin), Col-I (collagen type I), and Col-III (collagen type III), and improving pathological changes. EGT also significantly inhibited CCl4-induced hepatic inflammation and TGF-β/Smads signaling pathway. Metabolomics identified six key metabolic pathways, such as purine metabolism, glycerophospholipid metabolism, and sphingolipid metabolism, and eight key metabolites, such as xanthine, guanine, ATP, phosphatidylcholine, and sphingosine. Network pharmacology analysis showed that IL-17, cAMP and NF-κB signaling pathways were potential key mechanisms. Integrated analysis revealed that PLA2G2A might be a potential target of EGT against liver fibrosis. EGT may inhibit the glycerophospholipid metabolism through PLA2G2A to inhibit the TGF-β/Smads signaling pathway, thereby alleviating fibrosis. The present study indicates that EGT may be considered a valid therapeutic strategy to regress liver fibrosis, and provides novel insights into the pharmacological mechanism of EGT against liver fibrosis.

A guide to pathophysiology, signaling pathways, and preclinical models of liver fibrosis

Liver fibrosis is potentially a reversible form of liver disease that evolved from the early stage of liver scarring as a consequence of chronic liver injuries. Recurrent injuries in the liver without any appropriate medication cause the injuries to get intense and deeper, which gradually leads to the progression of irreversible cirrhosis or carcinoma. Unfortunately, there are no approved treatment strategies for reversing hepatic fibrosis, making it one of the significant risk factors for developing advanced liver disorders and liver disease-associated mortality. Consequently, the interpretation of the fundamental mechanisms, etiology, and pathogenesis is crucial for identifying the potential therapeutic target as well as evaluating novel anti-fibrotic therapy. However, despite innumerable research, the functional mechanism and disease characteristics are still obscure. To accelerate the understanding of underlying disease pathophysiology, molecular pathways and disease progression mechanism, it is crucial to mimic human liver disease through the formation of precise disease models. Although various in vitro and in vivo liver fibrotic models have emerged and developed already, a perfect clinical model replicating human liver diseases is yet to be established, which is one of the major challenges in discovering proper therapeutics. This review paper will shed light on pathophysiology, signaling pathways, preclinical models of liver fibrosis, and their limitations.

Mean platelet volume as a biomarker for liver fibrosis in patients with Non-alcoholic fatty liver disease

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent cause of chronic liver disease worldwide. Accurate assessment of liver fibrosis is essential for the prognosis and management of NAFLD. Mean platelet volume (MPV), an index of platelet activation, has been associated with liver fibrosis in various chronic liver diseases; however, its role in NAFLD remains uncertain.

METHODS

This study analyzed data from 70,830 patients with NAFLD who underwent a comprehensive health examination between 2015 and 2019. Patients were stratified into three groups based on the fibrosis-4 (FIB-4) index: low (<1.30), indeterminate (1.30-2.67), and high (>2.67). We evaluated the differences in MPV among these groups and analyzed the association between MPV and the FIB-4 index.

RESULTS

MPV varied significantly across the three groups categorized by the FIB-4 index (p < 0.001). Additionally, a weak but statistically significant positive correlation was observed between MPV and the FIB-4 index (rho =  0.170, p <  0.001). Multivariable linear regression adjusted for multiple covariates showed that MPV remained significantly associated with the FIB-4 index (β =  0.01, p <  0.001).

CONCLUSIONS

MPV may serve as a supplementary non-invasive marker for assessing liver fibrosis in patients with NAFLD. Further studies are required to validate these findings and explore the utility of MPV in conjunction with other non-invasive markers.

Metabolism of hepatic stellate cells in chronic liver diseases: emerging molecular and therapeutic interventions

Chronic liver diseases, primarily metabolic dysfunction-associated steatotic liver disease (MASLD), metabolic and metabolic dysfunction-associated alcoholic liver disease (MetALD), and viral hepatitis, can lead to liver fibrosis, cirrhosis, and cancer. Hepatic stellate cell (HSC) activation plays a central role in the development of myofibroblasts and fibrogenesis in chronic liver diseases. However, HSC activation is influenced by the complex microenvironments within the liver, which are largely shaped by the interactions between HSCs and various other cell types. Changes in HSC phenotypes and metabolic mechanisms involve glucose, lipid, and cholesterol metabolism, oxidative stress, activation of the unfolded protein response (UPR), autophagy, ferroptosis, senescence, and nuclear receptors. Clinical interventions targeting these pathways have shown promising results in addressing liver inflammation and fibrosis, as well as in modulating glucose and lipid metabolism and metabolic stress responses. Therefore, a comprehensive understanding of HSC phenotypes and metabolic mechanisms presents opportunities for novel therapeutic approaches aimed at halting or even reversing chronic liver diseases.

Platelet-Specific Deletion of TGF-β1 Impairs Septic Thrombosis in Mice-Brief Report

BACKGROUND

Sepsis is featured as a systemic inflammation and thrombosis induced by infection. TGF-β (transforming growth factor-β) 1 is mainly secreted from platelets and plays a role in immune response and inflammation. Whether platelet-derived TGF-β1 participates in sepsis remains unclear. This study intends to investigate its role in sepsis in mice.

METHODS

Platelet-specific TGF-β1 knockout mice received cecal ligation and puncture surgery to induce sepsis followed by the analysis of survival time, platelets number, pathology changes of lung and liver, liver function, the recruitment of platelets, neutrophils and monocytes, and neutrophil extracellular traps' formation. In addition, adoptive transfer of wild-type platelets into platelet-specific TGF-β1 knockout mice was performed to further evaluate the role of TGF-β1 in the pathogenesis of sepsis.

RESULTS

TGF-β1 level was gradually increased in the lung during the progress of sepsis, and platelets are the major source of the elevated TGF-β1 level in the lung after sepsis. Deficiency of platelet-derived TGF-β1 prolonged the survival of sepsis mice, inhibited the drop of platelet number and bacterial growth, impaired the thrombus formation in the lung and liver, and improved liver function. In addition, platelet TGF-β1 deficiency also decreased the recruitment of neutrophils and monocytes to the lung and impaired neutrophil extracellular trap formation. However, the adoptive transfer of normal platelets to platelet-specific TGF-β1 knockout mice significantly reduced the number of circulating platelets, increased thrombosis in the lung and liver, and promoted the neutrophil extracellular trap formation.

CONCLUSIONS

Deficiency of platelet-derived TGF-β1 inhibits septic thrombosis and prolongs survival time, indicating that it might be a novel therapeutic target for the treatment of sepsis.

N-Acetylcysteine Inhibits Aortic Stenosis Progression in a Murine Model by Blocking Shear-Induced Activation of Platelet Latent Transforming Growth Factor Beta 1

Objective: Aortic stenosis (AS) is characterized by narrowing of the aortic valve opening, resulting in peak blood flow velocity that induces high wall shear stress (WSS) across the valve. Severe AS leads to heart failure and death. There is no treatment available for AS other than valve replacement. Platelet-derived transforming growth factor beta 1 (TGF-β1) partially contributes to AS progression in mice, and WSS is a potent activator of latent TGF-β1. N-acetylcysteine (NAC) inhibits WSS-induced TGF-β1 activation in vitro. We hypothesize that NAC will inhibit AS progression by inhibiting WSS-induced TGF-β1 activation. Approach: We treated a cohort of Ldlr(-/-)Apob(100/100) low density lipoprotein receptor (LDLR) mice fed a high-fat diet with NAC (2% in drinking water) at different stages of disease progression and measured its effect on AS progression and TGF-β1 activation. Results: Short-term NAC treatment inhibited AS progression in mice with moderate and severe AS relative to controls, but not in LDLR mice lacking platelet-derived TGF-β1 (TGF-β1platlet-KO-LDLR). NAC treatment reduced TGF-β signaling, p-Smad2 and collagen levels, and mesenchymal transition from isolectin B4 and CD45-positive cells in LDLR mice. Mechanistically, NAC treatment resulted in plasma NAC concentrations ranging from 75.5 to 449.2 ng/mL, which were sufficient to block free thiol labeling of plasma proteins and reduce active TGF-β1 levels without substantially affecting reactive oxygen species-modified products in valvular cells. Conclusions: Short-term treatment with NAC inhibits AS progression by inhibiting WSS-induced TGF-β1 activation in the LDLR mouse model of AS, motivating a clinical trial of NAC and/or other thiol-reactive agent(s) as a potential therapy for AS.

Resveratrol Alleviates Liver Fibrosis Induced by Long-Term Inorganic Mercury Exposure through Activating the Sirt1/PGC-1α Signaling Pathway

Liver disease has become an important risk factor for global health. Resveratrol (Res) is a natural polyphenol which is widely found in foods and has a variety of biological activities. This study investigated the role of the microbiota-gut-liver axis in the Res relieving the liver fibrosis induced by inorganic mercury exposure. Twenty-eight mice were divided into four groups (n = 7) and treated with mercuric chloride and/or Res for 24 weeks, respectively. The results showed that Res mitigated the ileum injury induced by inorganic mercury and restrained LPS and alcohol entering the body circulation. Network pharmacological and molecular analyses showed that Res alleviated oxidative stress, metabolism disorders, inflammation, and hepatic stellate cell activation in the liver. In conclusion, Res alleviates liver fibrosis induced by inorganic mercury via activating the Sirt1/PGC-1α signaling pathway and regulating the microbial-gut-liver axis, particularly, increasing the relative enrichment of Bifidobacterium in the intestinal tract.

Platelet-Derived TGF-β1 Promotes Deep Vein Thrombosis

BACKGROUND

 Transforming growth factor-β1 (TGF-β1) modulates multiple cellular functions during development and tissue homeostasis. A large amount of TGF-β1 is stored in platelet α-granules and released upon platelet activation. Whether platelet-derived TGF-β1 plays a role in venous thrombosis remains unclear. This study intends to assess the role of platelet-derived TGF-β1 in the development of venous thrombosis in mice.

MATERIAL AND METHODS

 TGF-β1flox/flox and platelet-specific TGF-β1-/- mice were utilized to assess platelet function in vitro, arterial thrombosis induced by FeCl3, tail bleeding time, prothrombin time (PT), activated partial thromboplastin time (APTT), and deep vein thrombosis induced through ligation of the inferior vena cava (IVC). The IVC sample was collected to measure accumulation of neutrophils, monocytes, and the formation of neutrophil extracellular traps (NETs) by immunofluorescence staining.

RESULTS

 TGF-β1 deficiency in platelets did not affect the number of circulating platelets, platelet aggregation, adenosine triphosphate release, and integrin αIIbβ3 activation. Meanwhile, TGF-β1 deficiency did not alter the arterial thrombus formation, hemostasis, and coagulation time (PT and APTT), but significantly impaired venous thrombus formation, inhibited the recruitment and accumulation of neutrophils and monocytes in thrombi, as well as reduced formation of NETs and platelet-neutrophil complex. In addition, adoptive transfer of TGF-β1flox/flox platelets to TGF-β1-/- mice rescued the impaired venous thrombus formation, recruitment of leukocytes and monocytes, as well as the NETs formation.

CONCLUSION

In conclusion, platelet-derived TGF-β1 positively modulates venous thrombus formation in mice, indicating that targeting TGF-β1 might be a novel approach for treating venous thrombosis without increasing the risk of bleeding.

Platelet, Antiplatelet Therapy and Metabolic Dysfunction-Associated Steatotic Liver Disease: A Narrative Review

Metabolic dysfunction-associated steatotic liver disease (MASLD) is not only related to traditional cardiovascular risk factors like type 2 diabetes mellitus and obesity, but it is also an independent risk factor for the development of cardiovascular disease. MASLD has been shown to be independently related to endothelial dysfunction and atherosclerosis. MASLD is characterized by a chronic proinflammatory response that, in turn, may induce a prothrombotic state. Several mechanisms such as endothelial and platelet dysfunction, changes in the coagulative factors, lower fibrinolytic activity can contribute to induce the prothrombotic state. Platelets are players and addresses of metabolic dysregulation; obesity and insulin resistance are related to platelet hyperactivation. Furthermore, platelets can exert a direct effect on liver cells, particularly through the release of mediators from granules. Growing data in literature support the use of antiplatelet agent as a treatment for MASLD. The use of antiplatelets drugs seems to exert beneficial effects on hepatocellular carcinoma prevention in patients with MASLD, since platelets contribute to fibrosis progression and cancer development. This review aims to summarize the main data on the role of platelets in the pathogenesis of MASLD and its main complications such as cardiovascular events and the development of liver fibrosis. Furthermore, we will examine the role of antiplatelet therapy not only in the prevention and treatment of cardiovascular events but also as a possible anti-fibrotic and anti-tumor agent.

The association between platelet-related parameters and nonalcoholic fatty liver disease in a metabolically healthy nonobese population

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease characterized by subclinical inflammation and is related to obesity and metabolic syndrome (MS), but it is also frequently observed in nonobese populations. We aimed to evaluate the relationship between the white blood cell count-to-mean platelet volume ratio (WBC/MPV), platelet-to-lymphocyte count ratio (PLR) and lymphocyte-monocyte ratio (LMR) in association with NAFLD, considering the presence of obesity and MS. Additionally, we aimed to investigate whether these parameters exhibited similar correlations in metabolic dysfunction-associated steatotic liver disease (MASLD) as observed in NAFLD. This cross-sectional study included subjects who underwent a comprehensive health evaluation, including blood tests and abdominal ultrasonography. Subgroup analyses were conducted based on obesity and MS. Out of a total 5929 subjects (3271 males, mean age 49.7 ± 10.6 years), 2253 (38.0%) had NAFLD. WBC/MPV was significantly higher, and PLR was significantly lower in subjects with NAFLD. In the analysis restricted to the nonobese (BMI < 25 kg/m2) population without MS, both WBC/MPV and PLR were independently associated with NAFLD: WBC/MPV (adjusted OR 3.366; 95% CI 2.238-5.066) and PLR (adjusted OR 0.997; 95% CI 0.996-0.999). When assessing the risk of NAFLD based on the WBC/MPV and PLR quartiles, the adjusted OR and 95% CI for the lowest quartile compared to the highest were 2.055 (95% CI 1.626-2.602) for WBC/MPV and 0.660 (95% CI 0.523-0.832) for PLR in the nonobese, metabolically healthy group. The levels of WBC/MPV and PLR were independently associated with NAFLD. Furthermore, in MASLD, an association with WBC/MPV, PLR and LMR was identified, similar to the results observed in NAFLD, even after adjusting for confounding variables. In conclusion, the present study demonstrated a significant association between NAFLD and platelet-related parameters, especially in nonobese, metabolically healthy subjects.

Fibroblasts and platelets: a face-to-face dialogue at the heart of cardiac fibrosis

Myocardial fibrosis is a feature found in most cardiac diseases and a key element contributing to heart failure and its progression. It has therefore become a subject of particular interest in cardiac research. Mechanisms leading to pathological cardiac remodeling and heart failure are diverse, including effects on cardiac fibroblasts, the main players in cardiac extracellular matrix synthesis, but also on cardiomyocytes, immune cells, endothelial cells, and more recently, platelets. Although transforming growth factor-β (TGF-β) is a primary regulator of fibrosis development, the cellular and molecular mechanisms that trigger its activation after cardiac injury remain poorly understood. Different types of anti-TGF-β drugs have been tested for the treatment of cardiac fibrosis and have been associated with side effects. Therefore, a better understanding of these mechanisms is of great clinical relevance and could allow us to identify new therapeutic targets. Interestingly, it has been shown that platelets infiltrate the myocardium at an early stage after cardiac injury, producing large amounts of cytokines and growth factors. These molecules can directly or indirectly regulate cells involved in the fibrotic response, including cardiac fibroblasts and immune cells. In particular, platelets are known to be a major source of TGF-β1. In this review, we have provided an overview of the classical cellular effectors involved in the pathogenesis of cardiac fibrosis, focusing on the emergent role of platelets, while discussing opportunities for novel therapeutic interventions.

Development and Validation of a Risk Prediction Model for NAFLD: A Study Based on a Physical Examination Population

Purpose

To construct and validate a precise and personalized predictive model for non-alcoholic fatty liver disease (NAFLD) to enhance NAFLD screening and healthcare administration.

Patients and Methods

A total of 730 participants' clinical information and outcome measurements were gathered and randomly divided into training and validation sets in a ratio of 3:7. Using the least absolute shrinkage and selection operator (LASSO) regression and multiple logistic regression, a nomogram was established to select risk predictor variables. The NAFLD prediction model was validated through the receiver operating characteristic (ROC) curve, calibration plot, and decision curve analysis (DCA).

Results

After random grouping, the cohort comprised 517 in the training set and 213 in the validation set. The prediction model employed nine of the 20 selected variables, namely gender, hypertension, waist circumference, body mass index, blood platelet, triglycerides, high-density lipoprotein cholesterol, plasma glucose, and alanine aminotransferase. ROC curve analysis yielded an area under the curve values of 0.877 (95% Confidence Interval [CI]: 0.848-0.907) for the training set and 0.871 (95% CI: 0.825-0.917) for the validation set. Optimal critical values were determined as 0.472 (0.786, 0.825) in the training set and 0.457 (0.743, 0.839) in the validation set. Calibration curves for both sets showed proximity to the ideal diagonal, with P-values of 0.972 and 0.370 for the training and validation sets, respectively (P > 0.05). DCA indicated favorable clinical applicability of the model.

Conclusion

We constructed a nomogram model that could complement traditional NAFLD detection methods, aiding in individualized risk assessment for NAFLD.

Protective effects of baicalin on diethyl nitrosamine-induced liver cirrhosis by suppressing oxidative stress and inflammation

Baicalin (BA) is a natural product extract with anti-inflammatory, antioxidant, and hepatoprotective properties. Given that the exact underlying mechanisms responsible for the impact of BA on liver cirrhosis remain ambiguous, a detailed investigation is sorely needed. Accordingly, a rat liver cirrhosis model was established via the intraperitoneal injection of diethyl nitrosamine (DEN, 100 mg/kg). Following the modeling, these rats were given BA (100 mg/kg) or N-acetylcysteine (NAC, 150 mg/kg) alone or in combination. The pathological morphology of rat liver tissues in each group was observed by hematoxylin and eosin staining and Masson's trichrome staining. The expression of fibrosis-related proteins was evaluated by Western blot, and the levels of liver function-related biochemical indexes, oxidative stress-related indexes, and inflammatory factors in the serum by enzyme-linked immunosorbent assays (ELISA). The level of mitochondrial reactive oxygen species was measured by flow cytometry. The results depicted that in the rat model of DEN-induced liver cirrhosis, BA reduced the expression of fibrosis-related proteins (collagen type I alpha 1, α-smooth muscle actin, and transforming growth factor-β1), thereby alleviating the structural fibrosis of liver tissue. Furthermore, BA could diminish the level of mitochondrial reactive oxygen species, and the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α), and monocyte chemotactic protein-1 (MCP-1), while promoting albumin, superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) levels. Notably, all these effects of BA above were strengthened following the combined treatment of BA and NAC. On the whole, BA suppresses liver fibrosis by inhibiting oxidative stress and inflammation, thereby exerting a hepatoprotective effect.

Macrophages and platelets in liver fibrosis and hepatocellular carcinoma

During fibrosis, (myo)fibroblasts deposit large amounts of extracellular matrix proteins, thereby replacing healthy functional tissue. In liver fibrosis, this leads to the loss of hepatocyte function, portal hypertension, variceal bleeding, and increased susceptibility to infection. At an early stage, liver fibrosis is a dynamic and reversible process, however, from the cirrhotic stage, there is significant progression to hepatocellular carcinoma. Both liver-resident macrophages (Kupffer cells) and monocyte-derived macrophages are important drivers of fibrosis progression, but can also induce its regression once triggers of chronic inflammation are eliminated. In liver cancer, they are attracted to the tumor site to become tumor-associated macrophages (TAMs) polarized towards a M2- anti-inflammatory/tumor-promoting phenotype. Besides their role in thrombosis and hemostasis, platelets can also stimulate fibrosis and tumor development by secreting profibrogenic factors and regulating the innate immune response, e.g., by interacting with monocytes and macrophages. Here, we review recent literature on the role of macrophages and platelets and their interplay in liver fibrosis and hepatocellular carcinoma.

The role of plateletcrit in Takayasu arteritis: A potential biomarker for disease activity and 6-month treatment response

OBJECTIVES

To determine the role of plateletcrit as a potential biomarker for disease activity and treatment response in Takayasu arteritis (TAK).

METHODS

Totally, 215 newly diagnosed TAK patients were consecutively enrolled. Demographic data, clinical manifestations, laboratory and imaging examinations, and treatment strategy were recorded at baseline and at each visit during the 6-month treatment period. Normal plateletcrit (0.1%-0.4%) and hyper-plateletcrit (>0.4%) observed at baseline were used as group criteria.

RESULTS

At baseline, the overall plateletcrit was 0.32 (0.24-0.38)%, with a normal and high level observed in 172 (80.00%) and 43 (20.00%) patients, respectively. Baseline plateletcrit was significantly higher in patients with active disease and associated with inflammatory biomarkers, including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and interleukin (IL)-6 (all p < .01). At 6 months, complete remission was achieved in 171 (79.53%) patients, and a significant decrease in plateletcrit was observed in these cases (p < .01). Patients with a normal baseline plateletcrit were more likely to achieve complete remission compared to those with a high baseline plateletcrit (HR = 4.65, 95% CI: 2.38-19.08, p < .01). In addition, ESR (p = .01) and IL-6 (p = .02) levels were still higher in patients with a high baseline plateletcrit at 6 months. Progression of vascular lesions was indicated in 18 (8.37%) patients at 6 months, and these patients also had significantly higher baseline plateletcrit (p = .03).

CONCLUSION

Plateletcrit levels were positively related to disease activity and inflammatory index in TAK. Importantly, patients with high baseline plateletcrit levels may show a worse treatment response at 6 months.

Theaflavine inhibits hepatic stellate cell activation by modulating the PKA/LKB1/AMPK/GSK3β cascade and subsequently enhancing Nrf2 signaling

Activation of hepatic stellate cells (HSCs) constitutes a crucial etiological factor leading to liver fibrosis. Theaflavine (TF) is a characteristic bioactive compound in fermented tea. Here, we found that TF attenuated the activation of LX-2 HSCs induced by transforming growth factor-β1 (TGF-β1). TF potentiated nuclear factor erythroid 2-related Factor 2 (Nrf2) signaling. Knockdown of Nrf2 abrogated TF-mediated resistance to TGF-β1. Liver kinase B1 (LKB1), AMP-activated kinase (AMPK), and glycogen synthase kinase-3β (GSK3β) are upstream regulators of Nrf2. TF modulated the LKB1/AMPK/GSK3β axis. Inhibition of AMPK or knockdown of LKB1 crippled TF-mediated potentiation of Nrf2. Protein kinase A (PKA) catalyzes LKB1 phosphorylation. In LX-2 cells, TF increased the LKB1/PKA interaction without affecting their contents. Inhibition of PKA abolished TF-mediated potentiation of LKB1/Nrf2 and abrogated the inhibitory effects of TF on their activation. TF also enhanced direct binding between purified catalytic subunit α of PKA (PKA-Cα) and LKB1 proteins in vitro. Molecular docking indicated that TF showed binding activity with both LKB1 and PKA-Cα proteins. In mouse primary HSCs, TF elevated LKB1/PKA-Cα binding, boosted LKB1 phosphorylation, potentiated Nrf2 and suppressed their spontaneous activation. PKA inhibition or LKB1 knockdown eliminated TF-mediated induction of Nrf2 and suppression of HSC activation. Furthermore, TF considerably alleviated CCl4-induced mouse liver fibrosis. In mouse livers, TF increased the LKB1/PKA-Cα interaction, upregulated LKB1 phosphorylation and modulated its downstream AMPK/GSK3β/Nrf2 cascade. Our findings collectively indicated that TF suppresses HSC activation. Mechanistically, TF elevated the LKB1/PKA interaction in HSCs, which increased LKB1 phosphorylation and subsequently modulated the downstream AMPK/GSK3β/Nrf2 axis.

Investigating the role of platelets and platelet-derived transforming growth factor-β in idiopathic pulmonary fibrosis

Transforming growth factor-β1 (TGFβ1) is the key profibrotic cytokine in idiopathic pulmonary fibrosis (IPF), but the primary source of this cytokine in this disease is unknown. Platelets have abundant stores of TGFβ1, although the role of these cells in IPF is ill-defined. In this study, we investigated whether platelets, and specifically platelet-derived TGFβ1, mediate IPF disease progression. Patients with IPF and non-IPF patients were recruited to determine platelet reactivity, and separate cohorts of patients with IPF were followed for mortality. To study whether platelet-derived TGFβ1 modulates pulmonary fibrosis (PF), mice with a targeted deletion of TGFβ1 in megakaryocytes and platelets (TGFβ1fl/fl.PF4-Cre) were used in the well-characterized bleomycin-induced pulmonary fibrosis (PF) animal model. In a discovery cohort, we found significantly higher mortality in patients with IPF who had elevated platelet counts within the normal range. However, our validation cohort did not confirm this observation, despite significantly increased platelets, neutrophils, active TGFβ1, and CCL5, a chemokine produced by inflammatory cells, in the blood, lung, and bronchoalveolar lavage (BAL) of patients with IPF. In vivo, we showed that despite platelets being readily detected within the lungs of bleomycin-treated mice, neither the degree of pulmonary inflammation nor fibrosis was significantly different between TGFβ1fl/fl.PF4-Cre and control mice. Our results demonstrate for the first time that platelet-derived TGFβ1 does not significantly mediate inflammation or fibrosis in a PF animal model. Furthermore, our human studies revealed blood platelet counts do not consistently predict mortality in IPF but other platelet-derived mediators, such as C-C chemokine ligand 5 (CCL5), may promote neutrophil recruitment and human IPF.NEW & NOTEWORTHY Platelets are a rich source of profibrotic TGFβ; however, the role of platelets in idiopathic pulmonary fibrosis (IPF) is unclear. We identified that patients with IPF have significantly more platelets, neutrophils, and active TGFβ in their airways than control patients. Using an animal model of IPF, we demonstrated that platelet-derived TGFβ does not significantly drive lung fibrosis or inflammation. Our findings offer a better understanding of platelets in both human and animal studies of IPF.

Tolerance of repeated toxic injuries of murine livers is associated with steatosis and inflammation

The human liver has a remarkable capacity to regenerate and thus compensate over decades for fibrosis caused by toxic chemicals, drugs, alcohol, or malnutrition. To date, no protective mechanisms have been identified that help the liver tolerate these repeated injuries. In this study, we revealed dysregulation of lipid metabolism and mild inflammation as protective mechanisms by studying longitudinal multi-omic measurements of liver fibrosis induced by repeated CCl₄ injections in mice (n = 45). Based on comprehensive proteomics, transcriptomics, blood- and tissue-level profiling, we uncovered three phases of early disease development-initiation, progression, and tolerance. Using novel multi-omic network analysis, we identified multi-level mechanisms that are significantly dysregulated in the injury-tolerant response. Public data analysis shows that these profiles are altered in human liver diseases, including fibrosis and early cirrhosis stages. Our findings mark the beginning of the tolerance phase as the critical switching point in liver response to repetitive toxic doses. After fostering extracellular matrix accumulation as an acute response, we observe a deposition of tiny lipid droplets in hepatocytes only in the Tolerant phase. Our comprehensive study shows that lipid metabolism and mild inflammation may serve as biomarkers and are putative functional requirements to resist further disease progression.

Liver Fibrosis Resolution: From Molecular Mechanisms to Therapeutic Opportunities

The liver is a critical system for metabolism in human beings, which plays an essential role in an abundance of physiological processes and is vulnerable to endogenous or exogenous injuries. After the damage to the liver, a type of aberrant wound healing response known as liver fibrosis may happen, which can result in an excessive accumulation of extracellular matrix (ECM) and then cause cirrhosis or hepatocellular carcinoma (HCC), seriously endangering human health and causing a great economic burden. However, few effective anti-fibrotic medications are clinically available to treat liver fibrosis. The most efficient approach to liver fibrosis prevention and treatment currently is to eliminate its causes, but this approach's efficiency is too slow, or some causes cannot be fully eliminated, which causes liver fibrosis to worsen. In cases of advanced fibrosis, the only available treatment is liver transplantation. Therefore, new treatments or therapeutic agents need to be explored to stop the further development of early liver fibrosis or to reverse the fibrosis process to achieve liver fibrosis resolution. Understanding the mechanisms that lead to the development of liver fibrosis is necessary to find new therapeutic targets and drugs. The complex process of liver fibrosis is regulated by a variety of cells and cytokines, among which hepatic stellate cells (HSCs) are the essential cells, and their continued activation will lead to further progression of liver fibrosis. It has been found that inhibiting HSC activation, or inducing apoptosis, and inactivating activated hepatic stellate cells (aHSCs) can reverse fibrosis and thus achieve liver fibrosis regression. Hence, this review will concentrate on how HSCs become activated during liver fibrosis, including intercellular interactions and related signaling pathways, as well as targeting HSCs or liver fibrosis signaling pathways to achieve the resolution of liver fibrosis. Finally, new therapeutic compounds targeting liver fibrosis are summarized to provide more options for the therapy of liver fibrosis.

MPZL1 promotes LUAD progression by enhancing tumor proliferation, invasion, migration and suppressing immune function via TGF-β1

Lung cancer is the leading cause of death worldwide, and lung adenocarcinoma (LUAD) is the most common form of lung cancer. The abnormally high expression of myelin protein zero-like 1 (MPZL1) promotes the malignant progression of various tumors. However, there is no relevant report on the functional role of MPZL1 in LUAU. In this study, we applied illumina sequencing to screen differentially expressed genes. Subsequently, MPZL1 was selected as hub gene for qRT-PCR and CCK8 assay. The expression level of MPZL1 was analyzed by immunohistochemistry, immunofluorescence, western blot and qRT-PCR. After silencing or overexpressing MPZL1, CCK8, EDU, clone formation, scratch healing, invasion, and nude mouse tumor-bearing experiments were performed to detect the abilities of cell proliferation, migration, invasion and tumorigenicity. Moreover, qRT-PCR, western blot, Co-IP and scratch healing assays were conducted to explore the transcriptional regulatory factors of MPZL1. Finally, the relationship between MPZL1 and immunotherapy was explored through public databases and validated in vivo. The results show that a total of 196 high-expressed genes and 496 low-expressed genes were screened. Differential genes are mainly enriched in cell proliferation and division, protein binding and other pathways and functions. MPZL1 was selected as the hub gene and upregulated in LUAD tissues and cells. Silencing MPZL1 inhibited the cell proliferation and cloning formation, and the growth of tumor. Conversely, overexpression of MPZL1 has the opposite effect. In addition, MPZL1 combines with the TGF-β1 to promote the progress of LUAD. Finally, we found that high expression of MPZL1 is negatively correlated with infiltration of CD8+ cells and may lead to immunotherapy resistance. In summary, this study revealed a new mechanism by which MPZL1 promotes LUAD progression by enhancing tumor proliferation, invasion, migration and suppressing immune function.

Exploration of potential mechanism of Rougan formula against hepatic fibrosis by network analysis and experimental assessment

ETHNOPHARMACOLOGICAL RELEVANCE

Rougan Formula (RG) has long been clinically applied to treat hepatic fibrosis in patients with different chronic liver diseases. However, the core active substances and the potential pharmacological mechanisms of RG remain unclear.

AIM OF THE STUDY

The purpose of this study is to explore bioactive components, key targets, and potential mechanisms of RG by performing network pharmacological analyses and experimental model validation.

MATERIALS AND METHODS

All chemical components in RG extract were identified using ultraperformance liquid chromatography-quadrupole/time-of-flight tandem mass technology. The candidate components and drug targets of RG, as well as disease-related genes, were extracted from TCMSP and GeneCards databases. The potential pathways related to genes were predicted by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. The core bioactive components, key targets, and signaling pathways were ultimately obtained by analyzing protein-protein interaction (PPI) and component-target-pathway (C-T-P) networks. Subsequently, the efficacy and underlying mechanisms of RG on hepatic fibrosis were experimentally validated in transforming growth factor-beta 1 (TGF-β1)-induced hepatic stellate cell activation model and CCL₄-induced hepatic fibrosis mouse model.

RESULTS

A total of 52 components in RG extract were obtained, and 22 of them were selected as the core bioactive components. Five hundred and thirty-nine overlapped targets were determined by matching drug targets with disease-related targets. The results of PPI and C-T-P network analyses revealed 100 key targets and 19 signaling pathways associated with RG efficacy. In vitro and in vivo studies further verified that RG exerted a significant anti-hepatic fibrotic effect by suppressing the activation of hepatic stellate cells by downregulating the TGF-β1/Smads signaling pathway.

CONCLUSIONS

These results may provide some evidence for further clinical research and development of RG formula as an effective and safe drug for hepatic fibrosis treatment.

Platelet tissue factor pathway inhibitor-α dampens cardiac thrombosis and associated fibrosis in mice

BACKGROUND

Tissue factor pathway inhibitor (TFPI) is the primary inhibitor of events initiating the blood coagulation pathway. Tfpi-/- mice die during embryonic development. The absence of protease-activated receptor (PAR) 4, the major thrombin receptor on mouse platelets, rescues Tfpi-/-mice to adulthood. Among the 3 TFPI isoforms in mice, TFPIα is the only isoform within platelets (pltTFPIα) and the only isoform that inhibits prothrombinase, the enzymatic complex that converts prothrombin to thrombin.

OBJECTIVES

To determine biological functions of pltTFPIα.

METHODS

Tfpi-/-/Par4-/- mice were irradiated and transplanted with bone marrow from mice lacking or containing pltTFPIα. Thus, PAR4 expression was restored in the recipient mice, which differed selectively by the presence or absence of pltTFPIα and lacked other forms of TFPI.

RESULTS

Recipient mice lacking pltTFPIα had reduced survival over the 200-day posttransplant period. Necropsy revealed radiation injury associated with large intraventricular platelet-rich thrombi, whereas other organs were not affected. Thrombi were associated with fibrotic presentations, including increased collagen deposition, periostin-positive activated fibroblasts, myofibroblasts, and macrophage infiltrates. Recipient mice containing pltTFPIα showed evidence of radiation injury but lacked heart pathology.

CONCLUSIONS

Tfpi-/-/Par4-/- mice develop severe cardiac fibrosis following irradiation and transplantation with bone marrow lacking pltTFPIα. This pathology is markedly reduced when the mice are transplanted with bone marrow containing pltTFPIα. Thus, in this model system pltTFPIα has an important physiological role in dampening pathological responses mediated by activated platelets within the heart tissue.

Application of tumor-educated platelets as new fluid biopsy markers in various tumors

The incidence of malignant tumors is increasing year by year. Early detection and diagnosis of malignant tumors can improve the prognosis of patients and prolong their life. Pathological biopsy is the current gold standard for diagnosis, but the results of pathological biopsy are affected by the sampling site and cannot fully reflect the nature of the disease. Moreover, the invasive nature of pathological biopsy limits repeated detection. Liquid biopsies are non-invasive and can be used for early detection and monitoring of tumors, which considered to represent a promising tool. Platelets make themselves to be one of the richest liquid biopsy sources by the capacity to take up proteins and nucleic acids and alter their megakaryocyte-derived transcripts and proteins in response to external signals, which are called tumor-educated platelets (TEPs). In this article, we will review the application of tumor-educated platelets in various malignancies (nasopharyngeal carcinoma, prostate cancer, lung cancer, glioblastoma, colorectal cancer, pancreas cancer, ovarian cancer, sarcoma, breast cancer and hepatocellular carcinoma) and provide theoretical basis for the research of TEPs in tumor diagnosis, monitoring and treatment.

The role of platelet-related parameters for the prediction of NAFLD in OSAHS patients

PURPOSE

As the detection of non-alcoholic fatty liver disease (NAFLD) is imperative for the prevention of its complications, we aimed to explore the predictive value of platelet to lymphocyte count ratio (PLR) and white blood cell count to mean platelet volume ratio (WBC/MPV) in relation to the occurrence of NAFLD among patients with obstructive sleep apnea-hypopnea syndrome (OSAHS).

METHODS

This was a cross-sectional study consisting of 351 patients with OSAHS (279 with and 72 without NAFLD). The logistic regression analysis was performed to estimate associations between PLR, WBC/MPV, and NAFLD. Finally, the receiver operating characteristic curve (ROC curve) was used to analyze the efficacy of PLR and WBC/MPV in NAFLD prediction.

RESULTS

Compared to the OSAHS-only group, there was a rising trend in AHI and TS90% in the OSAHS + NAFLD group. And the logistic regression analysis identified average oxygen saturation (MaSO₂), WBC/MPV and PLR as predicted factors (odds ratio [OR] = 1.134, P = 0.031; OR = 7.559, P = 0.018, OR = 0.980, P < 0.001, respectively) for NAFLD in OSAHS patients. Moreover, compared with WBC/MPV, PLR, FLI, and APRI, a combination of WBC/MPV and PLR presented the largest AUC for the detection of NAFLD in BMI < 28 kg/m² (0.753, 95% CI 0.684-0.822), and in age ≥ 60 years subgroup (0.786, 95% CI 0.692-0.880) in ROC analysis. Meanwhile, a combination of WBC/MPV and PLR presented the second largest AUC for the detection of NAFLD in all subjects (0.743, 95% CI 0.708-0.831), as well as in the age < 60 years subgroup (0.729, 95% CI 0.652-0.806), only ranked after FLI, suggesting the combination of WBC/MPV and PLR has a good predictive value for NAFLD in OSAHS patients.

CONCLUSION

We confirmed that the levels of WBC/MPV, PLR, and MaSO₂ were closely related to the occurrence of NAFLD among OSAHS patients. Furthermore, our results highlighted the clinical combination of WBC/MPV and PLR levels could act as a simple and effective biomarker for screening NAFLD in patients with OSAHS.

Oxygen Gradient Induced in Microfluidic Chips Can Be Used as a Model for Liver Zonation

Availability of oxygen plays an important role in tissue organization and cell-type specific metabolism. It is, however, difficult to analyze hypoxia-related adaptations in vitro because of inherent limitations of experimental model systems. In this study, we establish a microfluidic tissue culture protocol to generate hypoxic gradients in vitro, mimicking the conditions found in the liver acinus. To accomplish this, four microfluidic chips, each containing two chambers, were serially connected to obtain eight interconnected chambers. HepG2 hepatocytes were uniformly seeded in each chamber and cultivated under a constant media flow of 50 µL/h for 72 h. HepG2 oxygen consumption under flowing media conditions established a normoxia to hypoxia gradient within the chambers, which was confirmed by oxygen sensors located at the inlet and outlet of the connected microfluidic chips. Expression of Hif1α mRNA and protein was used to indicate hypoxic conditions in the cells and albumin mRNA and protein expression served as a marker for liver acinus-like zonation. Oxygen measurements performed over 72 h showed a change from 17.5% to 15.9% of atmospheric oxygen, which corresponded with a 9.2% oxygen reduction in the medium between chamber1 (inlet) and 8 (outlet) in the connected microfluidic chips after 72 h. Analysis of Hif1α expression and nuclear translocation in HepG2 cells additionally confirmed the hypoxic gradient from chamber1 to chamber8. Moreover, albumin mRNA and protein levels were significantly reduced from chamber1 to chamber8, indicating liver acinus zonation along the oxygen gradient. Taken together, microfluidic cultivation in interconnected chambers provides a new model for analyzing cells in a normoxic to hypoxic gradient in vitro. By using a well-characterized cancer cell line as a homogenous hepatocyte population, we also demonstrate that an approximate 10% reduction in oxygen triggers translocation of Hif1α to the nucleus and reduces albumin production.

Platelet-derived TGF-β1 is related to portal vein thrombosis in cirrhosis by promoting hypercoagulability and endothelial dysfunction

Background

Portal vein thrombosis (PVT) is a serious complication of cirrhosis accompanied by unclear pathogenesis. Transforming growth factor-beta (TGF-β) has been implicated in atherosclerosis and venous thrombosis whereas study regarding its part in PVT is lacking. The aim of this study was to explore the role of cytokine TGF-β1 in PVT and the potential mechanism.

Materials and methods

We included patients with cirrhotic gastroesophageal varices and divided them into two groups according to the presence of PVT. Serum levels of TGF-β1 were detected using Cytometric Bead Array kit and compared between two groups. Coagulation status was assessed using thromboelastography (TEG). Primary liver sinusoidal endothelial cells were treated with TGF-β1 and evaluated for endothelial dysfunction by RT-PCR.

Results

Our results uncovered that TGF-β1 (6,866.55 vs. 3,840.60 pg/ml, P = 0.015) significantly increased in the PVT group. Splenectomy might promote PVT by increasing platelet-derived TGF-β1 levels. Other cytokines showed no difference between PVT and non-PVT groups. Besides, TGF-β1 was correlated with platelet, fibrinogen, TEG-CI, TEG-MA, and TEG-α (coef = 0.733, 0.494, 0.604, 0.608, and 0.511; P &lt; 0.001, 0.027, 0.004, 0.004, and 0.021, respectively), which indicated a hypercoagulable state in PVT patients. RT-PCR of liver sinusoidal endothelial cells showed a markable increment of von Willebrand Factor (vWF), thrombomodulin(TM), intercellular adhesion moleclar-1(ICAM-1), and vascular endothelial growth factor(VEGF) after TGF-β1 treatment, suggesting the involvement of endothelial dysfunction.

Conclusion

Elevated platelet-derived TGF-β1 exhibited association with hypercoagulability and promoting effect on endothelial dysfunction, closely related with PVT in cirrhotic patients.

Platelet TGF-β1 inhibits the migration and proliferation of smooth muscle cells in aneurysms

BACKGROUND

The study explored the role of platelet TGF-β1 from the perspective of inhibiting the excessive proliferation, migration and invasion of murine aortic vascular smooth muscle cells (MASMCs).

METHOD

The platelets were first extracted from C57BL/6 mice, and the TGF-β1 protein was obtained after the purification of protein. In vitro, the concentrations of angiotensin Ⅱ (Ang Ⅱ) and TGF-β1 for intervention were screened by testing the viability of MASMCs, followed by the analysis concerning the effects of platelets, Ang Ⅱ and TGF-β1 on the proliferation, migration, invasion, and the expressions of pathway-related proteins in MASMCs. In vivo, an Ang Ⅱ-induced mouse model was established. TGF-β1 was injected into the tail of mice as a therapeutic agent, and its action mechanism was further verified by the treatment of inhibitor SB505124. The results of the cell experiment were validated by evaluating the maximum diameter of abdominal aorta, the proportion of total weight, the changes of both pathology and the expressions of pathway-related proteins in the mice.

RESULT

0.5 ng/mL Ang Ⅱ and 15 ng/mL TGF-β1 were chosen for treatment. The following results of cell functional experiments and Western blot assay demonstrated that Ang Ⅱ promoted the proliferation, migration and invasion of MASMCs via regulating related pathways, the effects of which were evidently reversed by TGF-β1 and platelets. Consistent results were also observed in the animal experiments, where TGF-β1 effectively alleviated Ang Ⅱ-induced abdominal aortic injury in mice.

CONCLUSION

TGF-β1 in platelets inhibits Ang Ⅱ-induced proliferation, migration and invasion of MASMCs.

Design of a highly potent GLP-1R and GCGR dual-agonist for recovering hepatic fibrosis

Currently, there is still no effective curative treatment for the development of late-stage liver fibrosis. Here, we have illustrated that TB001, a dual glucagon-like peptide-1 receptor/glucagon receptor (GLP-1R/GCGR) agonist with higher affinity towards GCGR, could retard the progression of liver fibrosis in various rodent models, with remarkable potency, selectivity, extended half-life and low toxicity. Four types of liver fibrosis animal models which were induced by CCl₄, α-naphthyl-isothiocyanate (ANIT), bile duct ligation (BDL) and Schistosoma japonicum were used in our study. We found that TB001 treatment dose-dependently significantly attenuated liver injury and collagen accumulation in these animal models. In addition to decreased levels of extracellular matrix (ECM) accumulation during hepatic injury, activation of hepatic stellate cells was also inhibited via suppression of TGF-β expression as well as downstream Smad signaling pathways particularly in CCl₄-and S. japonicum-induced liver fibrosis. Moreover, TB001 attenuated liver fibrosis through blocking downstream activation of pro-inflammatory nuclear factor kappa B/NF-kappa-B inhibitor alpha (NFκB/IKBα) pathways as well as c-Jun N-terminal kinase (JNK)-dependent induction of hepatocyte apoptosis. Furthermore, GLP-1R and/or GCGR knock-down results represented GCGR played an important role in ameliorating CCl₄-induced hepatic fibrosis. Therefore, TB001 can be used as a promising therapeutic candidate for the treatment of multiple causes of hepatic fibrosis demonstrated by our extensive pre-clinical evaluation of TB001.

Megakaryocyte/platelet-derived TGF-β1 inhibits megakaryopoiesis in bone marrow by regulating thrombopoietin production in liver

Transforming growth factor β1 (TGF-β1) regulates a wide variety of events in the adult bone marrow, including quiescence of hematopoietic stem cells, via an undefined mechanism. Because megakaryocyte/platelets are a rich source of TGF-β1, we assessed whether TGF-β1 might inhibit its own production by comparing mice with conditional inactivation of Tgfb1 in megakaryocytes (PF4Cre;Tgfb1flox/flox) and control mice. PF4Cre;Tgfb1flox/flox mice had ~30% more megakaryocytes in BM and ~15% more circulating platelets than control mice (p<0.001). Thrombopoietin (TPO) levels in plasma and TPO expression in liver were ~2-fold higher in PF4Cre;Tgfb1flox/flox than in control mice (p<0.01), whereas the TPO expression in BM cells was similar between these mice. In BM cell culture, TPO treatment increased the number of megakaryocytes from WT-mice by ~3-fold, which increased a further ~2-fold in the presence of a TGF-β1-neutralizing antibody, and increased the number of megakaryocytes from PF4Cre;Tgfb1flox/flox mice ~5-fold. Our data reveal a new role for TGF-β1 produced by megakaryocyte/platelets in regulating its own production in BM via increasing TPO production in the liver. Further studies are required to determine the mechanism.

Immunohistochemical Expression of TGF-β1 in Kidneys of Cats with Chronic Kidney Disease

Transforming growth factor-beta 1 (TGF-β1) plays a central role in the progression of chronic kidney disease (CKD). However, in feline CKD, renal expression of TGF-β1 and how it changes as the disease progresses have not been fully studied. In the present study, we immunohistochemically assessed the renal expression levels of TGF-β1 in cats with CKD and statistically analyzed its correlation with CKD severity. Clear immunosignals were detected in the glomerular mesangial cells, Bowman’s capsules, proximal tubules, distal nephrons, platelets, and vascular smooth muscles in the kidneys of cats with CKD. Statistically, luminal signals in the distal nephrons showed positive correlations with plasma creatinine levels and glomerulosclerosis, while those in the proximal tubules and platelets showed negative correlations with plasma urea and/or creatinine levels. Therefore, it was suggested that the changes in the renal expression of TGF-β1 could be associated with progression of feline CKD.

Platelets in Non-alcoholic Fatty Liver Disease

Non alcoholic steatohepatitis (NASH) is the inflammatory reaction of the liver to excessive accumulation of lipids in the hepatocytes. NASH can progress to cirrhosis and hepatocellular carcinoma (HCC). Fatty liver is the hepatic manifestation of metabolic syndrome. A subclinical inflammatory state is present in patients with metabolic alterations like insulin resistance, type-2 diabetes, obesity, hyperlipidemia, and hypertension. Platelets participate in immune cells recruitment and cytokines-induced liver damage. It is hypothesized that lipid toxicity cause accumulation of platelets in the liver, platelet adhesion and activation, which primes the immunoinflammatory reaction and activation of stellate cells. Recent data suggest that antiplatelet drugs may interrupt this cascade and prevent/improve NASH. They may also improve some metabolic alterations. The pathophysiology of inflammatory liver disease and the implication of platelets are discussed in details.

Antiplatelet drugs and liver fibrosis

Liver fibrosis results from an imbalance between extracellular matrix formation and degradation. The background of liver fibrosis is chronic inflammation and subsequent microcirculation disturbance including microthrombosis. Platelets actively participate in liver fibrosis not only as a part of the clotting system but also by releasing granules containing important mediators. In fact, platelets may play a dual role in the pathophysiology of liver fibrosis as they are able to stimulate regeneration as well as aggravate the destruction of the liver. Recent studies revealed that antiplatelet therapy correlates with inhibition of liver fibrosis. However, liver impairment is associated with extensive coagulation disorders thus the safety of antiplatelet therapy is an area for detailed exploration. In this review, the role of platelets in liver fibrosis and accompanying hemostatic disorders are discussed. Additionally, results of animal and human studies on antiplatelet drugs in liver disorders and their potential therapeutic utility are presented.

A micellized bone morphogenetic protein-7 prodrug ameliorates liver fibrosis by suppressing transforming growth factor-β signaling

Bone morphogenetic protein-7 (BMP-7) antagonizes transforming growth factor-β (TGF-β), which is critically involved in liver fibrogenesis. Here, we designed a micelle formulation consisting of a protein transduction domain (PTD) fused BMP-7 polypeptide (mPTD-BMP-7) to enhance endocytic delivery, and investigated its ability to ameliorate liver fibrosis. The mPTD-BMP-7 formulation was efficiently delivered into cells via endocytosis, where it inhibited TGF-β mediated epithelial-mesenchymal transition. After successfully demonstrating delivery of fluorescently labeled mPTD-BMP-7 into the murine liver in vivo, we tested the mPTD-BMP-7 formulation in a murine liver fibrosis model, developed by repeated intraperitoneal injection of hepatotoxic carbon tetrachloride, twice weekly from 4 to 16 weeks. mPTD-BMP-7 effects were tested by injecting the mPTD-BMP-7 formulation (or vehicle control) into the lateral tail at a dose of 50 (n=8) or 500 μg/kg (n=10), also twice per week from 4 to 16 weeks. Vehicle-treated control mice developed fibrous septa surrounding the liver parenchyma and marked portal-to-portal bridging with occasional nodules, whereas mice treated with mPTD-BMP-7 showed only fibrous expansion of some portal areas, with or without short fibrous septa. Using the Ishak scoring system, we found that the fibrotic burden was significantly lower in mPTD-BMP-7 treated mice than in control mice (all P<0.001). Treatment with mPTD-BMP-7 protected tight junctions between hepatocytes and reduced extracellular matrix protein levels. It also significantly decreased mRNA levels of collagen 1A, smooth muscle α-actin, and connective tissue growth factor compared with that in control mice (all P<0.001). Collectively, out results indicate that mPTD-BMP-7, a prodrug formulation of BMP-7, ameliorates liver fibrosis by suppressing the TGF-β signaling pathway in a murine liver fibrosis model.

MAFLD/NAFLD Biopsy-Free Scoring Systems for Hepatic Steatosis, NASH, and Fibrosis Diagnosis

Metabolic dysfunction-associated fatty liver disease (MAFLD), formerly known as nonalcoholic fatty liver disease, is the most prevalent liver disorder worldwide. Historically, its diagnosis required biopsy, even though the procedure has a variable degree of error. Therefore, new non-invasive strategies are needed. Consequently, this article presents a thorough review of biopsy-free scoring systems proposed for the diagnosis of MAFLD. Similarly, it compares the severity of the disease, ranging from hepatic steatosis (HS) and nonalcoholic steatohepatitis (NASH) to fibrosis, by contrasting the corresponding serum markers, clinical associations, and performance metrics of these biopsy-free scoring systems. In this regard, defining MAFLD in conjunction with non-invasive tests can accurately identify patients with fatty liver at risk of fibrosis and its complications. Nonetheless, several biopsy-free scoring systems have been assessed only in certain cohorts; thus, further validation studies in different populations are required, with adjustment for variables, such as body mass index (BMI), clinical settings, concomitant diseases, and ethnic backgrounds. Hence, comprehensive studies on the effects of age, morbid obesity, and prevalence of MAFLD and advanced fibrosis in the target population are required. Nevertheless, the current clinical practice is urged to incorporate biopsy-free scoring systems that demonstrate adequate performance metrics for the accurate detection of patients with MAFLD and underlying conditions or those with contraindications of biopsy.

Fibrosis Is a Basement Membrane-Related Disease in the Cornea: Injury and Defective Regeneration of Basement Membranes May Underlie Fibrosis in Other Organs

Every organ develops fibrosis that compromises functions in response to infections, injuries, or diseases. The cornea is a relatively simple, avascular organ that offers an exceptional model to better understand the pathophysiology of the fibrosis response. Injury and defective regeneration of the epithelial basement membrane (EBM) or the endothelial Descemet's basement membrane (DBM) triggers the development of myofibroblasts from resident corneal fibroblasts and bone marrow-derived blood borne fibrocytes due to the increased entry of TGF beta-1/-2 into the stroma from the epithelium and tears or residual corneal endothelium and aqueous humor. The myofibroblasts, and disordered extracellular matrix these cells produce, persist until the source of injury is removed, the EBM and/or DBM are regenerated, or replaced surgically, resulting in decreased stromal TGF beta requisite for myofibroblast survival. A similar BM injury-related pathophysiology can underly the development of fibrosis in other organs such as skin and lung. The normal liver does not contain traditional BMs but develops sinusoidal endothelial BMs in many fibrotic diseases and models. However, normal hepatic stellate cells produce collagen type IV and perlecan that can modulate TGF beta localization and cognate receptor binding in the space of Dissé. BM-related fibrosis is deserving of more investigation in all organs.

pVHL-mediated SMAD3 degradation suppresses TGF-β signaling

Transforming growth factor β (TGF-β) signaling plays a fundamental role in metazoan development and tissue homeostasis. However, the molecular mechanisms concerning the ubiquitin-related dynamic regulation of TGF-β signaling are not thoroughly understood. Using a combination of proteomics and an siRNA screen, we identify pVHL as an E3 ligase for SMAD3 ubiquitination. We show that pVHL directly interacts with conserved lysine and proline residues in the MH2 domain of SMAD3, triggering degradation. As a result, the level of pVHL expression negatively correlates with the expression and activity of SMAD3 in cells, Drosophila wing, and patient tissues. In Drosophila, loss of pVHL leads to the up-regulation of TGF-β targets visible in a downward wing blade phenotype, which is rescued by inhibition of SMAD activity. Drosophila pVHL expression exhibited ectopic veinlets and reduced wing growth in a similar manner as upon loss of TGF-β/SMAD signaling. Thus, our study demonstrates a conserved role of pVHL in the regulation of TGF-β/SMAD3 signaling in human cells and Drosophila wing development.

Salvianolic acid B inhibits the progression of liver fibrosis in rats via modulation of the Hedgehog signaling pathway

Salvianolic acid B (Sal B) has previously reported anti-hepatic fibrosis effects, though it is not clear if it can inhibit hepatic fibrosis by regulating the hedgehog (Hh) signaling pathway. The aim of the present study was to explore the roles and mechanism of Sal B in preventing and treating liver fibrosis in rats. The study also aimed to determine the role of the Hh signaling pathway in this process. A rat model of liver fibrosis was induced through the subcutaneous injection of 50% carbon tetrachloride, followed by treatment with Sal B. After gavage, blood was collected to detect serum markers of liver injury. The degree of liver fibrosis and tissue damage was assessed using histopathological analysis. Western blotting and reverse transcription-quantitative PCR were used to detect the expression levels of TGF-β1 and Hh signaling pathway-related genes, including Sonic hedgehog (Shh) protein, membrane protein receptor protein patched homolog 1 (Ptch1), membrane protein receptor Smoothened (Smo) and transcription factor glioma-associated oncogene homolog 1 (Gli1). Serum alanine aminotransferase, aspartate aminotransferase and total bilirubin levels were decreased, whilst levels of albumin were increased in rats with liver fibrosis that were treated with Sal B (P<0.05). Additionally, significant increases in TGF-β1, Shh, Ptch1, Smo, Gli1 and α-smooth muscle actin expression levels were observed in the liver tissues of rats with hepatic fibrosis (P<0.05). However, Sal B treatment significantly reduced the expression levels of these proteins (P<0.05). In conclusion, the results of the present study suggested that the Hh signaling pathway may be activated during the process of rat liver fibrosis. Thus, Sal B may exert its anti-hepatic fibrosis effects, at least in part, by inhibiting the activation of the Hh signaling pathway.

Umbilical cord blood plasma-derived exosomes as a novel therapy to reverse liver fibrosis

Background

Cirrhosis is a chronic liver disease whereby scar tissue replaces healthy liver parenchyma, leading to disruption of the liver architecture and hepatic dysfunction. Currently, there is no effective disease-modifying therapy for liver fibrosis. Recently, our group demonstrated that human umbilical cord blood (UCB) plasma possesses therapeutic effects in a rat model of acute liver failure.

Methods

In the current study, we tested whether exosomes (Exo) existed in UCB plasma and if they produced any antifibrotic benefits in a liver fibrosis model.

Results

Our results showed that UCB-Exo improved liver function and increased matrix metalloproteinase/tissue inhibitor of metalloproteinase degradation to reduce the degree of fibrosis. Moreover, UCB-Exo were found to suppress hepatic stellate cell (HSC) activity in vitro. These effects were associated with suppression of transforming growth factor-β/inhibitor of DNA binding 1 signaling.

Conclusions

These results further support that UCB-Exo have antifibrotic effects in mice with liver fibrosis and activated HSCs and may herald a new cell-free antifibrotic therapy.

MicroRNA-497 induced by Clonorchis sinensis enhances the TGF-β/Smad signaling pathway to promote hepatic fibrosis by targeting Smad7

Background

Various stimuli, including Clonorchis sinensis infection, can cause liver fibrosis. Liver fibrosis is characterized by the activation of hepatic stellate cells (HSCs) with massive production of extracellular matrix (ECM). Our previous study showed that the TGF-β₁-induced Smad signaling pathway played a critical role in the activation of HSCs during liver fibrosis induced by worm infection; however, the mechanisms that modulate the TGF-β/Smad signaling pathway are still poorly understood. Accumulating evidence demonstrates that miRNAs act as an important regulator of activation of HSCs during liver fibrosis.

Methods

The target of miR-497 was determined by bioinformatics analysis combined with a dual-luciferase activity assay. LX-2 cells were transfected with miR-497 inhibitor and then stimulated with TGF-β₁ or excretory/secretory products of C. sinensis (CsESPs), and activation of LX-2 was assessed using qPCR or western blot. In vivo, the mice treated with CCl₄ were intravenously injected with a single dose of adeno-associated virus serotype 8 (AAV8) that overexpressed anti-miR-497 sequences or their scramble control for 6 weeks. Liver fibrosis and damage were assessed by hematoxylin and eosin (H&E) staining, Masson staining, and qPCR; the activation of the TGF-β/Smad signaling pathway was detected by qPCR or western blot.

Results

In the present study, the expression of miR-497 was increased in HSCs activated by TGF-β₁ or ESPs of C. sinensis. We identified that Smad7 was the target of miR-497 using combined bioinformatics analysis with luciferase activity assays. Transfection of anti-miR-497 into HSCs upregulated the expression of Smad7, leading to a decrease in the level of p-Smad2/3 and subsequent suppression of the activation of HSCs induced by TGF-β₁ or CsESPs. Furthermore, miR-497 inhibitor delivered by highly-hepatotropic (rAAV8) inhibited TGF-β/smads signaling pathway by targeting at Smad7 to ameliorate CCL4-induced liver fibrosis.

Conclusions

The present study demonstrates that miR-497 promotes liver fibrogenesis by targeting Smad7 to promote TGF-β/Smad signaling pathway transduction both in vivo and in vitro, which provides a promising therapeutic strategy using anti-miR-497 against liver fibrosis.

Graphical Abstract

Crosstalk between hepatic stellate cells and surrounding cells in hepatic fibrosis

Hepatic fibrosis represents as a dynamic pathological process characterized by the net accumulation of extracellular matrix in the progression of various chronic liver diseases, including viral hepatitis, alcoholic liver disease, and metabolic associated fatty liver disease (MAFLD). Activation of hepatic stellate cells (HSCs) is well-defined to play a central role in the initiation and progression of hepatic fibrosis. However, the activation of HSCs is affected by the complicated microenvironments in liver, which largely attributes to the communication between hepatocytes and multiple tissue-resident cells, including sinusoidal endothelial cells, bile duct epithelial cells, platelets, T cells, B cells, macrophages, natural killer cells, neutrophils, dendritic cells, in the direct or indirect mechanisms. Cellular crosstalk between HSCs and surrounding cells contributes to the activation of HSCs and the progression of hepatic fibrosis. Currently, accumulating evidence have proven the complexity and plasticity of HSCs activation, and further clarification of cellular communication between HSCs and surrounding cells will provide sufficient clue to the development of novel diagnostic methods and therapeutic strategies for hepatic fibrosis.

TGF-β Signaling in Liver, Pancreas, and Gastrointestinal Diseases and Cancer

Genetic alterations affecting transforming growth factor-β (TGF-β) signaling are exceptionally common in diseases and cancers of the gastrointestinal system. As a regulator of tissue renewal, TGF-β signaling and the downstream SMAD-dependent transcriptional events play complex roles in the transition from a noncancerous disease state to cancer in the gastrointestinal tract, liver, and pancreas. Furthermore, this pathway also regulates the stromal cells and the immune system, which may contribute to evasion of the tumors from immune-mediated elimination. Here, we review the involvement of the TGF-β pathway mediated by the transcriptional regulators SMADs in disease progression to cancer in the digestive system. The review integrates human genomic studies with animal models that provide clues toward understanding and managing the complexity of the pathway in disease and cancer.

Integrating Spatial Transcriptomics and Single-Cell RNA-seq Reveals the Gene Expression Profling of the Human Embryonic Liver

The liver is one of vital organs of the human body, and it plays an important role in the metabolism and detoxification. Moreover, fetal liver is one of the hematopoietic places during ontogeny. Understanding how this complex organ develops during embryogenesis will yield insights into how functional liver replacement tissue can be engineered and how liver regeneration can be promoted. Here, we combine the advantages of single-cell RNA sequencing and Spatial Transcriptomics (ST) technology for unbiased analysis of fetal livers over developmental time from 8 post-conception weeks (PCW) and 17 PCW in humans. We systematically identified nine cell types, and defined the developmental pathways of the major cell types. The results showed that human fetal livers experienced blood rapid growth and immigration during the period studied in our experiments, and identified the differentially expressed genes, and metabolic changes in the developmental process of erythroid cells. In addition, we focus on the expression of liver disease related genes, and found that 17 genes published and linked to liver disease mainly expressed in megakaryocyte and endothelial, hardly expressed in any other cell types. Together, our findings provide a comprehensive and clear understanding of the differentiation processes of all main cell types in the human fetal livers, which may provide reference data and information for liver disease treatment and liver regeneration.

Activated platelets contribute to the progression of hepatocellular carcinoma by altering the tumor environment

AIM

Hepatocellular carcinoma (HCC) is a primary liver cancer that usually develops in a background of chronic liver disease and prolonged inflammation. A major contributor in the complex molecular pathogenesis of HCC is the highly intertwined cross-talk between the tumor and the surrounding stromal cells, such as hepatic stellate cells, endothelial cells, macrophages and other immune cells. These tumor-stroma interactions actively fuel tumor growth and modulate the hepatic microenvironment to benefit tumor invasion and disease progression. Platelets have been reported to interact with different cell types in the tumor microenvironment, including tumor cells, stellate cells and macrophages.

MATERIALS AND METHODS

Mice were treated with hepatocarcinogenic compound diethylnitrosamine for 25 weeks to induce HCC in the background of fibrosis and inflammation. From week 10, anti-platelet drug Clopidogrel was added to the drinking water and mice were given ad libitum access.

KEY FINDINGS

In this study, we show that activated platelets promote tumor cell proliferation and contribute to the adverse tumor-stroma cross-talk that fuels tumor progression. We also show that inhibiting platelet activation with the P2Y12-inhibitor Clopidogrel decreases the number of tumors in a chemically induced mouse model for HCC.

SIGNIFICANCE

These results suggest an important role for platelets in the pathogenesis of HCC and that the use of anti-platelet drugs may be therapeutically relevant for patients with liver cancer.

Interaction of non‑parenchymal hepatocytes in the process of hepatic fibrosis (Review)

Hepatic fibrosis (HF) is the process of fibrous scar formation caused by chronic liver injury of different etiologies. Previous studies have hypothesized that the activation of hepatic stellate cells (HSCs) is the central process in HF. The interaction between HSCs and surrounding cells is also crucial. Additionally, hepatic sinusoids capillarization, inflammation, angiogenesis and fibrosis develop during HF. The process involves multiple cell types that are highly connected and work in unison to maintain the homeostasis of the hepatic microenvironment, which serves a key role in the initiation and progression of HF. The current review provides novel insight into the intercellular interaction among liver sinusoidal endothelial cells, HSCs and Kupffer cells, as well as the hepatic microenvironment in the development of HF.

Nonalcoholic fatty liver disease (NAFLD) severity is associated to a nonhemostatic contribution and proinflammatory phenotype of platelets

Nonalcoholic fatty liver disease (NAFLD) is the main cause of chronic liver disease and ranges from simple steatosis to nonalcoholic steatohepatitis. Recently, a platelet role in NAFLD pathogenesis and progression has been reported in mouse models and in patients. We investigated whether platelets are involved in liver and systemic inflammation processes in NAFLD. In this exploratory study we recruited 24 consecutive patients with biopsy-proven diagnosis of NAFLD and 17 healthy volunteers. We measured plasma levels of inflammatory markers by ELISA. We investigated hemostatic and inflammatory transcripts in circulating platelets and leukocytes from NAFLD patients. We analyzed platelet and neutrophil extracellular traps (NET) accumulations in liver sinusoids using CD42 and H3 citrullinated histones immunohistochemical staining on liver biopsies. NAFLD patients had increased inflammation markers and lipolysaccharides plasma levels. We found significant increase of inflammatory transcripts in circulating platelets and not in leukocytes of NAFLD subjects compared with healthy controls. We demonstrated increased intrahepatic platelet accumulation that correlated with NAFLD activity score (NAS) score and intrahepatic neutrophil extracellular traps (NET) formation in liver biopsies of NAFLD patients. NET formation was higher in livers with higher NAS and inflammation scores. The presence of low-grade systemic inflammation and proinflammatory changes of circulating platelets indicate that platelets participate on systemic inflammatory changes associated with NAFLD. Liver platelet accumulation and liver NET formation, together with low-grade endotoxemia, suggest that platelets may act to protect the liver from invading microorganisms by favoring local NET formation.

Blood Platelets as an Important but Underrated Circulating Source of TGFβ

When treating diseases related primarily to tissue remodeling and fibrosis, it is desirable to regulate TGFβ concentration and modulate its biological effects. The highest cellular concentrations of TGFβ are found in platelets, with about 40% of all TGFβ found in peripheral blood plasma being secreted by them. Therefore, an understanding of the mechanisms of TGFβ secretion from platelets may be of key importance for medicine. Unfortunately, despite the finding that platelets are an important regulator of TGFβ levels, little research has been carried out into the development of platelet-directed therapies that might modulate the TGFβ-dependent processes. Nevertheless, there are some very encouraging reports suggesting that platelet TGFβ may be specifically involved in cardiovascular diseases, liver fibrosis, tumour metastasis, cerebral malaria and in the regulation of inflammatory cell functions. The purpose of this review is to briefly summarize these few, extremely encouraging reports to indicate the state of current knowledge in this topic. It also attempts to better characterize the influence of TGFβ on platelet activation and reactivity, and its shaping of the roles of blood platelets in haemostasis and thrombosis.

Till Death Do Us Part-The Multifaceted Role of Platelets in Liver Diseases

Platelets are tightly connected with the liver, as both their production and their clearance are mediated by the liver. Platelets, in return, participate in a variety of liver diseases, ranging from non-alcoholic fatty liver diseases, (viral) hepatitis, liver fibrosis and hepatocellular carcinoma to liver regeneration. Due to their versatile functions, which include (1) regulation of hemostasis, (2) fine-tuning of immune responses and (3) release of growth factors and cellular mediators, platelets quickly adapt to environmental changes and modulate disease development, leading to different layers of complexity. Depending on the (patho)physiological context, platelets exert both beneficial and detrimental functions. Understanding the precise mechanisms through which platelet function is regulated at different stages of liver diseases and how platelets interact with various resident and non-resident liver cells helps to draw a clear picture of platelet-related therapeutic interventions. Therefore, this review summarizes the current knowledge on platelets in acute and chronic liver diseases and aims to shed light on how the smallest cells in the circulatory system account for changes in the (patho)physiology of the second largest organ in the human body.