The roles and potential mechanisms of plant polysaccharides in liver diseases: a review.

Plant polysaccharides (PP) demonstrate a diverse array of biological and pharmacological properties. This comprehensive review aims to compile and present the multifaceted roles and underlying mechanisms of plant polysaccharides in various liver diseases. These diseases include non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), fibrosis, drug-induced liver injury (DILI), and hepatocellular carcinoma (HCC). This study aims to elucidate the intricate mechanisms and therapeutic potential of plant polysaccharides, shedding light on their significance and potential applications in the management and potential prevention of these liver conditions. An exhaustive literature search was conducted for this study, utilizing prominent databases such as PubMed, Web of Science, and CNKI. The search criteria focused on the formula "(plant polysaccharides liver disease) NOT (review)" was employed to ensure the inclusion of original research articles up to the year 2023. Relevant literature was extracted and analyzed from these databases. Plant polysaccharides exhibit promising pharmacological properties, particularly in the regulation of glucose and lipid metabolism and their anti-inflammatory and immunomodulatory effects. The ongoing progress of studies on the molecular mechanisms associated with polysaccharides will offer novel therapeutic strategies for the treatment of chronic liver diseases (CLDs).

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

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.

Design and Synthesis of Novel Ultralong-Acting Peptides as EDP-EBP Interaction Inhibitors for Pulmonary Fibrosis Treatment.

The increased remodeling of the extracellular matrix (ECM) in pulmonary fibrosis (PF) generates bioactive ECM fragments called matricryptins, which include elastin-derived peptides (EDPs). The interaction between EDPs and their receptors, including elastin-binding protein (EBP), plays a crucial role in exacerbating fibrosis. Here, we present LXJ-02 for the first time, a novel ultralong-acting inhibitor that disrupts the EDPs/EBP peptide-protein interaction, promoting macrophages to secrete matrix metalloproteinase-12 (MMP-12), and showing great promise as a stable peptide. MMP-12 has traditionally been implicated in promoting inflammation and fibrosis in various acute and chronic diseases. However, we reveal a novel role of LXJ-02 that activates the macrophage-MMP-12 axis to increase MMP-12 expression and degrade ECM components like elastin. This leads to the preventing of PF while also improving EDP-EBP interaction. LXJ-02 effectively reverses PF in mouse models with minimal side effects, holding great promise as an excellent therapeutic agent for lung fibrosis.

Design and discovery of a highly potent ultralong-acting GLP-1 and glucagon co-agonist for attenuating renal fibrosis.

The role of co-agonists of glucagon-like peptide-1 receptor (GLP-1R) and glucagon receptor (GCGR) in chronic kidney disease (CKD) remains unclear. Herein we found that GLP-1R and GCGR expression levels were lower in the kidneys of mice with CKD compared to healthy mice and were correlated with disease severity. Interestingly, GLP-1R or GCGR knockdown aggravated the progression of kidney injury in both diabetic db/db mice and non-diabetic mice undergoing unilateral ureteral obstruction (UUO). Based on the importance of GLP-1R and GCGR in CKD, we reported a novel monomeric peptide, 1907-B, with dual-agonism on both GLP-1R and GCGR. The data confirmed that 1907-B had a longer half-life than long-acting semaglutide in rats or cynomolgus monkeys (∼2-3 fold) and exhibited better therapeutic contribution to CKD than best-in-class monoagonists, semaglutide, or glucagon, in db/db mice and UUO mice. Various lock-of-function models, including selective pharmacological activation and genetic knockdown, confirmed that 1907-B's effects on ameliorating diabetic nephropathy in db/db mice, as well as inhibiting kidney fibrosis in UUO mice, were mediated through GLP-1 and glucagon signaling. These findings highlight that 1907-B, a novel GLP-1R and GCGR co-agonist, exerts multifactorial improvement in kidney injuries and is an effective and promising therapeutic option for CKD treatment.

Harnessing the Lysosomal Sorting Signals of the Cation-Independent Mannose-6-Phosphate Receptor for Targeted Degradation of Membrane Proteins.

Membrane proteins are a crucial class of therapeutic targets that remain challenging to modulate using traditional occupancy-driven inhibition strategies or current proteolysis-targeting degradation approaches. Here, we report that the inherent endolysosomal sorting machinery can be harnessed for the targeted degradation of membrane proteins. A new degradation technique, termed signal-mediated lysosome-targeting chimeras (SignalTACs), was developed by genetically fusing the signaling motif from the cation-independent mannose-6-phosphate receptor (CI-M6PR) to a membrane protein binder. Antibody-based SignalTACs were constructed with the CI-M6PR signal peptides fused to the C-terminus of both heavy and light chains of IgG. We demonstrated the scope of this platform technology by degrading five pathogenesis-related membrane proteins, including HER2, EGFR, PD-L1, CD20, and CD71. Furthermore, two simplified constructs of SignalTACs, nanobody-based and peptide-based SignalTACs, were created and shown to promote the lysosomal degradation of target membrane proteins. Compared to the parent antibodies, SignalTACs exhibited significantly higher efficiency in inhibiting tumor cell growth both in vitro and in vivo. This work provides a simple, general, and robust strategy for degrading membrane proteins with molecular precision and may represent a powerful platform with broad research and therapeutic applications.

Discovery and Design of Novel Cyclic Peptides as Specific Inhibitors Targeting CCN2 and Disrupting CCN2/EGFR Interaction for Kidney Fibrosis Treatment.

Kidney fibrosis is a serious consequence of chronic kidney disease (CKD), and currently, there is no effective pharmacological treatment available. Cellular communication network-2 (CCN2/CTGF) is an extracellular matrix (ECM) protein that regulates the fibrotic process by activating the epidermal growth factor receptor (EGFR) signaling pathway. We herein present the discovery and structure-activity relationship study of novel peptides targeting CCN2 to develop potent and stable specific inhibitors of the CCN2/EGFR interaction. Remarkably, the 7-mer cyclic peptide OK2 exhibited potent activities to inhibit CCN2/EGFR-induced STAT3 phosphorylation and cellular ECM protein synthesis. Subsequent in vivo studies demonstrated that OK2 significantly alleviated renal fibrosis in a unilateral ureteral obstruction (UUO) mouse model. Moreover, this study first revealed that the peptide candidate could efficiently block CCN2/EGFR interaction through binding to the CT domain of CCN2, providing a new alternative strategy for peptide-based targeting of CCN2 and modulating CCN2/EGFR-mediated biological functions in kidney fibrosis.

Synergistic activation of AMPK by AdipoR1/2 agonist and inhibitor of EDPs-EBP interaction recover NAFLD through enhancing mitochondrial function in mice.

Nonalcoholic fatty liver disease (NAFLD), especially nonalcoholic steatohepatitis (NASH), is a common hepatic manifestation of metabolic syndrome. However, there are no effective therapy to treat this devastating disease. Accumulating evidence suggests that the generation of elastin-derived peptides (EDPs) and the inhibition of adiponectin receptors (AdipoR)1/2 plays essential roles in hepatic lipid metabolism and liver fibrosis. We recently reported that the AdipoR1/2 dual agonist JT003 significantly degraded the extracellular matrix (ECM) and ameliorated liver fibrosis. However, the degradation of the ECM lead to the generation of EDPs, which could further alter liver homeostasis negatively. Thus, in this study, we successfully combined AdipoR1/2 agonist JT003 with V14, which acted as an inhibitor of EDPs-EBP interaction to overcome the defect of ECM degradation. We found that combination of JT003 and V14 possessed excellent synergistic benefits on ameliorating NASH and liver fibrosis than either alone since they compensate the shortage of each other. These effects are induced by the enhancement of the mitochondrial antioxidant capacity, mitophagy, and mitochondrial biogenesis via AMPK pathway. Furthermore, specific suppression of AMPK could block the effects of the combination of JT003 and V14 on reduced oxidative stress, increased mitophagy and mitochondrial biogenesis. These positive results suggested that this administration of combination of AdipoR1/2 dual agonist and inhibitor of EDPs-EBP interaction can be recommended alternatively for an effective and promising therapeutic strategy for the treatment of NAFLD and NASH related fibrosis.

Design and Discovery of Novel Cyclic Peptides as EDPs-EBP Interaction Inhibitors for the Treatment of Liver Fibrosis.

Liver fibrosis is the undesirable result of excessive deposition of the extracellular matrix (ECM), and elastin is known as one of the key ECM components. Under specific pathological conditions, elastin undergoes degradation to produce elastin-derived peptides (EDPs), which bind to elastin-binding protein (EBP) to activate corresponding signal pathways, thus accelerating fibrosis progression. Herein, we describe the discovery of novel cyclic peptides that function as potent and stable inhibitors to interfere with the peptide-protein interaction between EDPs and EBP. Remarkably, CXJ-2 exhibited potent activities to inhibit the PI3K/ERK pathway and decrease hepatic stellate cell proliferation and migration. The subsequent in vivo study demonstrated that CXJ-2 possessed potent antifibrotic efficacy in ameliorating CCl4-induced liver fibrosis. This work provides a successful pharmacological strategy for the development of novel inhibitors of EDPs-EBP interaction, which sheds new light on how cyclic peptides disrupt peptide-protein interaction and may also provide new structure-oriented therapeutic candidates in liver fibrosis.

Different Performances of BF3, BCl3, and BBr3 in Hypervalent Iodine-Catalyzed Halogenations.

Herein, hypervalent iodine-catalyzed halogenation of aryl-activated alkenes using BX3 (X = Cl, Br) as the halogen source and activating reagents was reported. Various halogenated 1,3-oxazine/2-oxazoline derivatives were obtained in good-to-high yields. Using BF3 resulted in different substitute sites from BBr3 and BCl3 of the products, indicating different reactive intermediates and reaction pathways. The reaction underwent a "ligand coupling/oxidative addition/intermolecular nucleophilic attack/1,2-aryl migration/reductive elimination/intramolecular nucleophilic attack" cascade when BF3 was applied as the halogen source, while 1,2-aryl migration has "disappeared" when the halogen source was BBr3 or BCl3. Possible catalytic cycles were proposed, and DFT calculations were conducted to demonstrate the differences among BX3 (X = F, Cl, Br) in the hypervalent iodine-catalyzed halogenations.

Structure-Guided Design of Halofuginone Derivatives as ATP-Aided Inhibitors Against Bacterial Prolyl-tRNA Synthetase.

Aminoacyl-tRNA synthetases (aaRSs) are promising antimicrobial targets due to their essential roles in protein translation, and expanding their inhibitory mechanisms will provide new opportunities for drug discovery. We report here that halofuginone (HF), an herb-derived medicine, moderately inhibits prolyl-tRNA synthetases (ProRSs) from various pathogenic bacteria. A cocrystal structure of Staphylococcus aureus ProRS (SaProRS) with HF and an ATP analog was determined, which guided the design of new HF analogs. Compound 3 potently inhibited SaProRS at IC50 = 0.18 µM and Kd = 30.3 nM and showed antibacterial activities with an MIC of 1-4 µg/mL in vitro. The bacterial drug resistance to 3 only developed at a rate similar to or slower than those of clinically used antibiotics in vitro. Our study indicates that the scaffold and ATP-aided inhibitory mechanism of HF could apply to bacterial ProRS and also provides a chemical validation for using bacterial ProRS as an antibacterial target.

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-ß 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.

Development, validation and application of a UHPLC-MS/MS method for quantification of the adiponectin-derived active peptide ADP355 in rat plasma.

A UHPLC-MS/MS method for the quantification of ADP355, an adiponectin-derived active peptide, was developed and validated. The extraction method employed simple protein precipitation using methanol and chromatographic separation was achieved on anAccucore™ RP-MS C18 column (100 × 2.1 mm, 2.6 µm, 80 Å), using 0.1% formic acid in both water and acetonitrile with gradient elution at the flow rate of 400 µl/min within 4.0 min. Detections were performed under positive ion mode with multiple reaction monitoring ion transitions m/z 1109.2 → 309.8 and 871.4 → 310.1 for ADP355 and Jt003 respectively at unit resolution. The linearity range of the calibration curve was 2-1,000 ng/ml with a lower limit detection of 0.5 ng/ml. The selectivity, linearity, precision, accuracy, recovery, matrix effect and stability were validated, and all items met the requirement of US Food and Drug Administration guidance. This method was successfully applied to an intravenous pharmacokinetic study of ADP355 in rats and the in-vitro stability in rat serum, plasma and whole blood was also assessed.

Dual Blockade of Lactate/GPR81 and PD-1/PD-L1 Pathways Enhances the Anti-Tumor Effects of Metformin.

Metformin is a widely used antidiabetic drug for cancer prevention and treatment. However, the overproduction of lactic acid and its inefficiency in cancer therapy limit its application. Here, we demonstrate the synergistic effects of the lactate/GPR81 blockade (3-hydroxy-butyrate, 3-OBA) and metformin on inhibiting cancer cells growth in vitro. Simultaneously, this combination could inhibit glycolysis and OXPHOS metabolism, as well as inhibiting tumor growth and reducing serum lactate levels in tumor-bearing mice. Interestingly, we observed that this combination could enhance the functions of Jurkat cells in vitro and CD8+ T cells in vivo. In addition, considering that 3-OBA could recover the inhibitory effects of metformin on PD-1 expression, we further determined the dual blockade effects of PD-1/PD-L1 and lactate/GPR81 on the antitumor activity of metformin. Our results suggested that this dual blockade strategy could remarkably enhance the anti-tumor effects of metformin, or even lead to tumor regression. In conclusion, our study has proposed a novel and robust strategy for a future application of metformin in cancer treatment.

Catalytic asymmetric nucleophilic fluorination using BF3·Et2O as fluorine source and activating reagent.

Fluorination using chiral catalytic methods could result in a direct access to asymmetric fluorine chemistry. However, challenges in catalytic asymmetric fluorinations, especially the longstanding stereochemical challenges existed in BF3·Et2O-based fluorinations, have not yet been addressed. Here we report the catalytic asymmetric nucleophilic fluorination using BF3·Et2O as the fluorine reagent in the presence of chiral iodine catalyst. Various chiral fluorinated oxazine products were obtained with good to excellent enantioselectivities (up to >99% ee) and diastereoselectivities (up to >20:1 dr). Control experiments (the desired fluoro-oxazines could not be obtained when Py·HF or Et3N·3HF were employed as the fluorine source) indicated that BF3·Et2O acted not only as a fluorine reagent but also as the activating reagent for activation of iodosylbenzene.

A CDR-based approach to generate covalent inhibitory antibody for human rhinovirus protease.

Covalent target modulation with small molecules has been emerging as a promising strategy for drug discovery. However, covalent inhibitory antibody remains unexplored due to the lack of efficient strategies to engineer antibody with desired bioactivity. Herein, we developed an intracellular selection method to generate covalent inhibitory antibody against human rhinovirus 14 (HRV14) 3C protease through unnatural amino acid mutagenesis along the heavy chain complementarity-determining region 3 (CDR-H3). A library of antibody mutants was thus constructed and screened in vivo through co-expression with the target protease. Using this screening strategy, six covalent antibodies with proximity-enabled bioactivity were identified, which were shown to covalently target HRV14-3C protease with high inhibitory potency and exquisite selectivity. Compared to structure-based rational design, this library-based screening method provides a simple and efficient way for the discovery and engineering of covalent antibody for enzyme inhibition.

Visible-Light-Driven Redox Neutral Direct C-H Amination of Glycine Derivatives and Peptides with N-Acyloxyphthalimides.

A room temperature, visible-light-promoted and redox neutral direct C-H amination of glycine and peptides has been firstly accomplished by using N-acyloxyphthalimide or -succinimide as nitrogen-radical precursor. The present strategy provides ways to introduce functionalities such as N-acyloxyphthalimide or -succinimide specifically to terminal glycine segment of peptides. Herein, mild conditions and high functional-group tolerance allow the preparation of non-natural α-amino acids and modification of corresponding peptides in this way.

The antimicrobial peptide YD attenuates inflammation via miR-155 targeting CASP12 during liver fibrosis.

The antimicrobial peptide APKGVQGPNG (named YD), a natural peptide originating from Bacillus amyloliquefaciens CBSYD1, exhibited excellent antibacterial and antioxidant properties in vitro. These characteristics are closely related to inflammatory responses which is the central trigger for liver fibrosis. However, the therapeutic effects of YD against hepatic fibrosis and the underlying mechanisms are rarely studied. In this study, we show that YD improved liver function and inhibited the progression of liver fibrosis by measuring the serum transaminase activity and the expression of α-smooth muscle actin and collagen I in carbon tetrachloride-induced mice. Then we found that YD inhibited the level of miR-155, which plays an important role in inflammation and liver fibrosis. Bioinformatics analysis and luciferase reporter assay indicate that Casp12 is a new target of miR-155. We demonstrate that YD significantly decreases the contents of inflammatory cytokines and suppresses the NF-κB signaling pathway. Further studies show that transfection of the miR-155 mimic in RAW264.7 cells partially reversed the YD-mediated CASP12 upregulation, the downregulated levels of inflammatory cytokines, and the inactivation of the NF-κB pathways. Collectively, our study indicates that YD reduces inflammation through the miR-155-Casp12-NF-κB axis during liver fibrosis and provides a promising therapeutic candidate for hepatic fibrosis.

Development of a Broadly Applicable Cas12a-Linked Beam Unlocking Reaction for Sensitive and Specific Detection of Respiratory Pathogens Including SARS-CoV-2.

The outbreak of novel coronavirus SARS-CoV-2 has caused a worldwide threat to public health. COVID-19 patients with SARS-CoV-2 infection can develop clinical symptoms that are often confused with the infections of other respiratory pathogens. Sensitive and specific detection of SARS-CoV-2 with the ability to discriminate from other viruses is urgently needed for COVID-19 diagnosis. Herein, we streamlined a highly efficient CRISPR-Cas12a-based nucleic acid detection platform, termed Cas12a-linked beam unlocking reaction (CALIBURN). We show that CALIBURN could detect SARS-CoV-2 and other coronaviruses and influenza viruses with little cross-reactivity. Importantly, CALIBURN allowed accurate diagnosis of clinical samples with extremely low viral loads, which is a major obstacle for the clinical applications of existing CRISPR diagnostic platforms. When tested on the specimens from SARS-CoV-2-positive and negative donors, CALIBURN exhibited 73.0% positive and 19.0% presumptive positive rates and 100% specificity. Moreover, unlike existing CRISPR detection methods that were mainly restricted to respiratory specimens, CALIBURN displayed consistent performance across both respiratory and nonrespiratory specimens, suggesting its broad specimen compatibility. Finally, using a mouse model of SARS-CoV-2 infection, we demonstrated that CALIBURN allowed detection of coexisting pathogens without cross-reactivity from a single tissue specimen. Our results suggest that CALIBURN can serve as a versatile platform for the diagnosis of COVID-19 and other respiratory infectious diseases.

AdipoR1/AdipoR2 dual agonist recovers nonalcoholic steatohepatitis and related fibrosis via endoplasmic reticulum-mitochondria axis.

Chronic nonalcoholic steatohepatitis (NASH) is a metabolic disorder that often leads to liver fibrosis, a condition with limited therapy options. Adiponectin is an adipocytokine that regulates glucose and lipid metabolism via binding to its receptors AdipoR1 and AdipoR2, and AdipoRs signaling is reported to enhance fatty acid oxidation and glucose uptake. Here, we synthesize and report an adiponectin-based agonist JT003, which potently improves insulin resistance in high fat diet induced NASH mice and suppresses hepatic stellate cells (HSCs) activation in CCl4 induced liver fibrosis. Mechanistic studies indicate that JT003 simultaneously stimulates AdipoR1- and AdipoR2- mediated signaling pathways as well as the PI3K-Akt pathway. Moreover, JT003 treatment significantly improves ER-mitochondrial axis function, which contributes to the reduced HSCs activation. Thus, the AdipoR1/AdipoR2 dual agonist improves both NASH and fibrosis in mice models, which provides the pharmacological and biological foundation for developing AdipoRs-based therapeutic agents on liver fibrosis.