Single-cell transcriptomic dissection of the cellular and molecular events underlying the triclosan-induced liver fibrosis in mice

Background: Triclosan [5-chloro-2-(2,4-dichlorophenoxy) phenol, TCS], a common antimicrobial additive in many personal care and health care products, is frequently detected in human blood and urine. Therefore, it has been considered an emerging and potentially toxic pollutant in recent years. Long-term exposure to TCS has been suggested to exert endocrine disruption effects, and promote liver fibrogenesis and tumorigenesis. This study was aimed at clarifying the underlying cellular and molecular mechanisms of hepatotoxicity effect of TCS at the initiation stage.Methods: C57BL/6 mice were exposed to different dosages of TCS for 2 weeks and the organ toxicity was evaluated by various measurements including complete blood count, histological analysis and TCS quantification. Single cell RNA sequencing(scRNA-seq) was then carried out on TCS-or mock-treated mice livers to delineate the TCS-induced hepatotoxicity. The acquired single-cell transcriptomic data were analyzed from different aspects including differential gene expression, transcription factor(TF) regulatory network, pseudotime trajectory, and cellular communication, to systematically dissect the cellular and molecular events after TCS exposure. To verify the TCS-induced liver fibrosis,the expression levels of key fibrogenic proteins were examined by Western blotting, immunofluorescence, Masson’s trichrome and Sirius red stainings. In addition, normal hepatocyte cell MIHA and hepatic stellate cell LX-2 were used as in vitro cell models to experimentally validate the effects of TCS by immunological, proteomic and metabolomic technologies.Results: We established a relatively short term TCS exposure murine model and found the TCS mainly accumulated in the liver. The scRNA-seq performed on the livers of the TCS-treated and control groups profiled the gene expressions of > 76,000 cells belonging to 13 major cell types. Among these types, hepatocytes and hepatic stellate cells(HSCs)were significantly increased in TCS-treated group. We found that TCS promoted fibrosis-associated proliferation of hepatocytes, in which Gata2 and Mef2c are the key driving TFs. Our data also suggested that TCS induced the proliferation and activation of HSCs, which was experimentally verified in both liver tissue and cell model. In addition,other changes including the dysfunction and capillarization of endothelial cells, an increase of fibrotic characteristics in B plasma cells, and M2 phenotype-skewing of macrophage cells, were also deduced from the scRNA-seq analysis, and these changes are likely to contribute to the progression of liver fibrosis. Lastly, the key differential ligand-receptor pairs involved in cellular communications were identified and we confirmed the role of GAS6_AXL interactionmediated cellular communication in promoting liver fibrosis.Conclusions: TCS modulates the cellular activities and fates of several specific cell types(including hepatocytes, HSCs,endothelial cells, B cells, Kupffer cells and liver capsular macrophages) in the liver, and regulates the ligand-receptor interactions between these cells, thereby promoting the proliferation and activation of HSCs, leading to liver fibrosis.Overall, we provide the first comprehensive single-cell atlas of mice livers in response to TCS and delineate the key cellular and molecular processes involved in TCS-induced hepatotoxicity and fibrosis.

A single-cell landscape of triptolide-associated testicular toxicity in mice

Triptolide is a key active component of the widely used traditional Chinese herb medicine Tripterygium wilfordii Hook.F.Although triptolide exerts multiple biological activities and shows promising efficacy in treating inflammatory-related diseases,its well-known safety issues,especially reproductive toxicity has aroused concerns.However,a comprehensive dissection of triptolide-associated testicular toxicity at single cell resolution is still lacking.Here,we observed testicular toxicity after 14 days of triptolide exposure,and then constructed a single-cell transcriptome map of 59,127 cells in mouse testes upon triptolide-treatment.We identified triptolide-associated shared and cell-type specific differentially expressed genes,enriched pathways,and ligand-receptor pairs in different cell types of mouse testes.In addition to the loss of germ cells,our results revealed increased macrophages and the inflammatory response in triptolide-treated mouse testes,suggesting a critical role of inflammation in triptolide-induced testicular injury.We also found increased reactive oxygen species(ROS)signaling and downregulated pathways associated with spermatid development in somatic cells,especially Leydig and Sertoli cells,in triptolide-treated mice,indicating that dysregulation of these signaling pathways may contribute to triptolide-induced testicular toxicity.Overall,our high-resolution single-cell landscape offers comprehensive information regarding triptolide-associated gene expression profiles in major cell types of mouse testes at single cell resolution,providing an invaluable resource for understanding the underlying mechanism of triptolide-associated testicular injury and additional discoveries of therapeutic targets of triptolide-induced male reproductive toxicity.

Single-cell transcriptome analysis reveals the regulatory effects of artesunate on splenic immune cells in polymicrobial sepsis

Sepsis is characterized by a severe and life-threatening host immune response to polymicrobial infection accompanied by organ dysfunction.Studies on the therapeutic effect and mechanism of immunomodulatory drugs on the sepsis-induced hyperinflammatory or immunosuppression states of various immune cells remain limited.This study aimed to investigate the protective effects and underlying mechanism of artesunate(ART)on the splenic microenvironment of cecal ligation and puncture-induced sepsis model mice using single-cell RNA sequencing(scRNA-seq)and experimental validations.The scRNA-seq analysis revealed that ART inhibited the activation of pro-inflammatory macrophages recruited during sepsis.ART could restore neutrophils’chemotaxis and immune function in the septic spleen.It inhibited the activation of T regulatory cells but promoted the cytotoxic function of natural killer cells during sepsis.ART also promoted the differentiation and activity of splenic B cells in mice with sepsis.These results indicated that ART could alleviate the inflammatory and/or immunosuppressive states of various immune cells involved in sepsis to balance the immune homeostasis within the host.Overall,this study provided a comprehensive investigation of the regulatory effect of ART on the splenic microenvironment in sepsis,thus contributing to the application of ART as adjunctive therapy for the clinical treatment of sepsis.

Single-cell transcriptome analysis uncovers underlying mechanisms of acute liver injury induced by tripterygium glycosides tablet in mice

Tripterygium glycosides tablet(TGT),the classical commercial drug of Tripterygium wilfordii Hook.F.has been effectively used in the treatment of rheumatoid arthritis,nephrotic syndrome,leprosy,Behcet's syndrome,leprosy reaction and autoimmune hepatitis.However,due to its narrow and limited treatment window,TGT-induced organ toxicity(among which liver injury accounts for about 40%of clinical reports)has gained increasing attention.The present study aimed to clarify the cellular and molecular events underlying TGT-induced acute liver injury using single-cell RNA sequencing(scRNA-seq)technology.The TGT-induced acute liver injury mouse model was constructed through short-term TGT exposure and further verified by hematoxylin-eosin staining and liver function-related serum indicators,including alanine aminotransferase,aspartate aminotransferase,alkaline phosphatase and total bilirubin.Using the mouse model,we identified 15 specific subtypes of cells in the liver tissue,including endothelial cells,hepatocytes,cholangiocytes,and hepatic stellate cells.Further analysis indicated that TGT caused a significant inflammatory response in liver endothelial cells at different spatial locations;led to marked inflammatory response,apoptosis and fatty acid metabolism dysfunction in hepatocytes;activated hepatic stellate cells;brought about the activation,inflammation,and phagocytosis of liver capsular macrophages cells;resulted in immune dysfunction of liver lymphocytes;disturbed the intercellular crosstalk in liver microenvironment by regulating various signaling pathways.Thus,these findings elaborate the mechanism underlying TGT-induced acute liver injury,provide new insights into the safe and rational applications in the clinic,and complement the identification of new biomarkers and therapeutic targets for liver protection.

Mechanistic engineering of celastrol liposomes induces ferroptosis and apoptosis by directly targeting VDAC2 in hepatocellular carcinoma

Hepatocellular carcinoma(HCC)is one of most common and deadliest malignancies.Celastrol(Cel),a natural product derived from the Tripterygium wilfordii plant,has been extensively researched for its potential effectiveness in fighting cancer.However,its clinical application has been hindered by the unclear mechanism of action.Here,we used chemical proteomics to identify the direct targets of Cel and enhanced its targetability and antitumor capacity by developing a Cel-based liposomes in HCC.We demonstrated that Cel selectively targets the voltage-dependent anion channel 2(VDAC2).Cel directly binds to the cysteine residues of VDAC2,and induces cytochrome C release via dysregulating VDAC2-mediated mitochondrial permeability transition pore(mPTP)function.We further found that Cel induces ROS-mediated ferroptosis and apoptosis in HCC cells.Moreover,coencapsulation of Cel into alkyl glucoside-modified liposomes(AGCL)improved its antitumor efficacy and minimized its side effects.AGCL has been shown to effectively suppress the proliferation of tumor cells.In a xenograft nude mice experiment,AGCL significantly inhibited tumor growth and promoted apoptosis.Our findings reveal that Cel directly targets VDAC2 to induce mitochondria-dependent cell death,while the Cel liposomes enhance its targetability and reduces side effects.Overall,Cel shows promise as a therapeutic agent for HCC.

Single-cell transcriptomics reveals the ameliorative effect of rosmarinic acid on diabetic nephropathy-induced kidney injury by modulating oxidative stress and inflammation

Diabetic nephropathy(DN)is a severe complication of diabetes,characterized by changes in kidney structure and function.The natural product rosmarinic acid(RA)has demonstrated therapeutic effects,including anti-inflammation and anti-oxidative-stress,in renal damage or dysfunction.In this study,we characterized the heterogeneity of the cellular response in kidneys to DN-induced injury and RA treatment at single cell levels.Our results demonstrated that RA significantly alleviated renal tubular epithelial injury,particularly in the proximal tubular S1 segment and on glomerular epithelial cells known as podocytes,while attenuating the inflammatory response of macrophages,oxidative stress,and cytotox-icity of natural killer cells.These findings provide a comprehensive understanding of the mechanisms by which RA alleviates kidney damage,oxidative stress,and inflammation,offering valuable guidance for the clinical application of RA in the treatment of DN.

Research progress on the role of extracellular vesicles in neurodegenerative diseases

Neurodegenerative diseases,such as Alzheimer’s disease,Parkinson’s disease,amyotrophic lateral sclerosis,and Huntington’s disease,affect millions of people worldwide.Tremendous efforts have been put into disease-related research,but few breakthroughs have been made in diagnostic and therapeutic approaches.Extracellular vesicles(EVs)are heterogeneous cell-derived membrane structures that arise from the endosomal system or are directly separated from the plasma membrane.EVs contain many biomolecules,including proteins,nucleic acids,and lipids,which can be transferred between different cells,tissues,or organs,thereby regulating cross-organ communication between cells during normal and pathological processes.Recently,EVs have been shown to participate in various aspects of neurodegenerative diseases.Abnormal secretion and levels of EVs are closely related to the pathogenesis of neurodegenerative diseases and contribute to disease progression.Numerous studies have proposed EVs as therapeutic targets or biomarkers for neurodegenerative diseases.In this review,we summarize and discuss the advanced research progress on EVs in the pathological processes of several neurodegenerative diseases.Moreover,we outline the latest research on the roles of EVs in neurodegenerative diseases and their therapeutic potential for the diseases.

Single-cell transcriptomics systematically discloses the immune-inflammatory responses of peripheral blood mononuclear cells for diabetic nephropathy

Diabetic nephropathy(DN)has become the leading cause of end-stage renal disease with high morbidity and mortality among individuals with diabetes mellitus.Although functional alterations of renal infiltrating immune cells have been reported as part of the pathological mechanism of DN,the understanding of the immune response underlying peripheral blood mononuclear cells(PBMCs)in DN remains limited.Here,single-cell RNA sequencing(scRNA-seq)was used toprofile the transcriptomic signatures of PBMCs from DN patients.

Chemical proteomic profling with photoaffinity labeling strategy identifies antimalarial targets of artemisinin

Present research on the antimalarial mechanisms of artemisinin(ART)is mainly focused on covalent drug binding targets alkylated by free radicals,while non-covalent binding targets have rarely been reported.Here,we developed a novel photoaffinity probe of ART to globally capture and identify the antimalarial target proteins of ART through chemical proteomics.The results demonstrated that ART can bind to par-asite proteins by both covalent and non-covalent modification,and these may jointly contribute to the antimalarial effects.Our work enriches the research on the antimalarial targets of ART,and provides a new perspective for further exploring the antimalarial mechanism of ART.

New advances in gated materials of mesoporous silica for drug controlled release

Drug delivery systems(DDS) are used to deliver therapeutic drugs to improve selectivity and reduce side effects. With the development of nanotechnology, many nanocarriers have been developed and applied to drug delivery, including mesoporous silica. Mesoporous silica nanoparticles(MSNs) have attracted a lot of attention for simple synthesis, biocompatibility, high surface area and pore volume. Based on the pore system and surface modification, gated mesoporous silica nanoparticles can be designed to realize on-command drug release, which provides a new approach for selective delivery of antitumor drugs.Herein, this review mainly focuses on the “gate keepers” of mesoporous silica for drug controlled release in nearly few years(2017–2020). We summarize the mechanism of drug controlled release in gated MSNs and different gated materials: inorganic gated materials, organic gated materials, self-gated drug molecules, and biological membranes. The facing challenges and future prospects of gated MSNs are discussed rationally in the end.