The Pharmacokinetics and Liver-Targeting Evaluation of Silybin Liposomes Mediated by the NTCP/OCTN2 Dual Receptors.

The disadvantage of a traditional dosage regimen is the inability to deliver a sufficient drug concentration to the lesion site, which can result in adverse side effects due to nonspecific drug delivery. Actively targeting hepatic cells is a promising therapeutic strategy for liver disease. In this study, l-carnitine and a targeting peptide derived from the hepatitis B virus large envelope protein were used to modify liposomes for drug delivery to the liver through the sodium taurocholate cotransporting polypeptide (NTCP) and the organic cation/carnitine transporter 2 (OCTN2) receptors. Silybin was selected as the model drug. The solubility of silybin can reach 0.3 mg/mL after encapsulation in liposomes. The NTCP-specific and OCTN2-accelerated Myrcludex B and l-carnitine dual-modified liposomes were validated in vitro. The uptake of coumarin-6 in dual ligand-modified liposomes by hepatocytes was up to 2.36 µg/mg compared with unmodified liposomes (1.05 µg/mg). The pharmacokinetics and targeting abilities of various liposome formulations were evaluated in Kunming mice. Targeted liposomes increased the concentration of silybin and prolonged the drug's retention time in the liver. The area under the liver's pharmacokinetic curve of targeted liposomes was twice that of silybin injection, suggesting the promising application potential of silybin-loaded hepatotropic nanovesicles.

Tauroursodeoxycholic Acid Improves Nonalcoholic Fatty Liver Disease by Regulating Gut Microbiota and Bile Acid Metabolism.

Tauroursodeoxycholic acid (TUDCA) is a synthetic bile salt that has demonstrated efficacy in the management of hepatobiliary disorders. However, its specific mechanism of action in preventing and treating nonalcoholic fatty liver disease (NAFLD) remains incompletely understood. This research revealed that TUDCA treatment can reduce obesity and hepatic lipid buildup, enhance intestinal barrier function and microbial balance, and increase the presence of Allobaculum and Bifidobacterium in NAFLD mouse models. TUDCA can influence the activity of farnesoid X receptor (FXR) and cholesterol 7α-hydroxylase (CYP7A1), resulting in higher hepatic bile acid levels and increased expression of sodium taurocholate cotransporting polypeptide (NTCP), leading to elevated concentrations of liver-bound bile acids in mice. Furthermore, TUDCA can inhibit the expression of FXR and fatty acid transport protein 5 (FATP5), thereby reducing fatty acid absorption and hepatic lipid accumulation. This investigation provides new insights into the potential of TUDCA for preventing and treating NAFLD.

Both middle and large envelope proteins can mediate neutralization of hepatitis B virus infectivity by anti-preS2 antibodies: escape by naturally occurring preS2 deletions.

Hepatitis B virus (HBV) expresses co-terminal large (L), middle (M), and small (S) envelope proteins containing preS1/preS2/S, preS2/S, and S domain alone, respectively. S and preS1 domains mediate sequential virion attachment to heparan sulfate proteoglycans and sodium taurocholate cotransporting polypeptide (NTCP), respectively, which can be blocked by anti-S and anti-preS1 antibodies. How anti-preS2 antibodies neutralize HBV infectivity remains enigmatic. The late stage of chronic HBV infection often selects for mutated preS2 translation initiation codon to prevent M protein expression, or in-frame preS2 deletions to shorten both L and M proteins. When introduced to infectious clone of genotype C or D, both M-minus mutations and most 5' preS2 deletions sustained virion production. Such mutant progeny viral particles were infectious in NTCP-reconstituted HepG2 cells. Neutralization experiments were performed on the genotype D clone. Although remaining susceptible to anti-preS1 and anti-S neutralizing antibodies, M-minus mutants were only partially neutralized by two anti-preS2 antibodies tested while preS2 deletion mutants were resistant. By infection experiments using viral particles with lost versus increased M protein expression, or a neutralization escaping preS2 deletion only present on L or M protein, we found that both full-length L and M proteins contributed to virus neutralization by the two anti-preS2 antibodies. Thus, immune escape could be a driving force for the selection of M-minus mutations, and especially preS2 deletions. The fact that both L and M proteins could mediate neutralization by anti-preS2 antibodies may shed light on the underlying molecular mechanism.IMPORTANCEThe large (L), middle (M), and small (S) envelope proteins of hepatitis B virus (HBV) contain preS1/preS2/S, preS2/S, and S domain alone, respectively. The discovery of heparan sulfate proteoglycans and sodium taurocholate cotransporting polypeptide (NTCP) as the low- and high-affinity HBV receptors could explain neutralizing potential of anti-S and anti-preS1 antibodies, respectively, but how anti-preS2 neutralizing antibodies work remains enigmatic. In this study, we found two M-minus mutants in the context of genotype D partially escaped two anti-preS2 neutralizing antibodies in NTCP-reconstituted HepG2 cells, while several naturally occurring preS2 deletion mutants escaped both antibodies. By point mutations to eliminate or enhance M protein expression, and by introducing preS2 deletion selectively to L or M protein, we found binding of anti-preS2 antibodies to both L and M proteins contributed to neutralization of wild-type HBV infectivity. Our finding may shed light on the possible mechanism(s) whereby anti-preS2 antibodies neutralize HBV infectivity.

Inhibition of hepatic bile salt uptake by Bulevirtide reduces atherosclerosis in Oatp1a1-/-Ldlr-/- mice.

Bile salts can strongly influence energy metabolism through systemic signaling, which can be enhanced by inhibiting the hepatic bile salt transporter Na+ taurocholate cotransporting polypeptide (NTCP), thereby delaying hepatic reuptake of bile salts to increase systemic bile salt levels. Bulevirtide is an NTCP inhibitor and was originally developed to prevent NTCP-mediated entry of Hepatitis B and D into hepatocytes. We previously demonstrated that NTCP inhibition lowers body weight, induces glucagon-like peptide-1 (GLP1) secretion, and lowers plasma cholesterol levels in murine obesity models. In humans, a genetic loss-of-function variant of NTCP has been associated with reduced plasma cholesterol levels. Here, we aimed to assess if Bulevirtide treatment attenuates atherosclerosis development by treating female Ldlr-/- mice with Bulevirtide or vehicle for 11 weeks. Since this did not result in the expected increase in plasma bile salt levels, we generated Oatp1a1-/-Ldlr-/- mice, an atherosclerosis-prone model with human-like hepatic bile salt uptake characteristics. These mice showed delayed plasma clearance of bile salts and elevated bile salt levels upon Bulevirtide treatment. At the study endpoint, Bulevirtide-treated female Oatp1a1-/-Ldlr-/- mice had reduced atherosclerotic lesion area in the aortic root that coincided with lowered plasma LDL-c levels, independent of intestinal cholesterol absorption. In conclusion, Bulevirtide, which is considered safe and is EMA-approved for the treatment of Hepatitis D, reduces atherosclerotic lesion area by reducing plasma LDL-c levels. We anticipate that its application may extend to atherosclerotic cardiovascular diseases, which warrants clinical trials.

The GLP-1 Receptor Agonist Liraglutide Decreases Primary Bile Acids and Serotonin in the Colon Independently of Feeding in Mice.

Liraglutide, a glucagon-like peptide 1 analog used to treat type 2 diabetes and obesity, is a potential new treatment modality for bile acid (BA) diarrhea. Here, we show that administration of liraglutide significantly decreased total BAs, especially the primary BAs, including cholic acid, chenodeoxycholic acid, taurocholic acid, taurochenodeoxycholic acid, glycocholic acid, and ß-muricholic acid, in the liver and feces. In addition, liraglutide significantly decreased tryptophan metabolites, including L-tryptophan, serotonin, 5-hydroxy indole-3-acetic acid, L-kynurenine, and xanthurenic acid, in the colon, whereas it significantly increased indole-3-propionic acid. Moreover, the administration of liraglutide remarkably decreased the expression of apical sodium-dependent bile acid transporter, which mediates BA uptake across the apical brush border member in the ileum, ileal BA binding protein, and fibroblast growth factor 15 in association with decreased expression of the BA-activated nuclear receptor farnesoid X receptor and the heteromeric organic solute transporter Ostα/ß, which induces BA excretion, in the ileum. Liraglutide acutely decreased body weight and blood glucose levels in association with decreases in plasma insulin and serotonin levels in food-deprived mice. These findings suggest the potential of liraglutide as a novel inhibitor of primary BAs and serotonin in the colon.

Farnesoid X Receptor: Effective alleviation of rifampicin -induced liver injury.

Antituberculosis drugs induce pharmacologic cholestatic liver injury with long-term administration. Liver injury resulting from rifampicin is potentially related to the bile acid nuclear receptor Farnesoid X Receptor (FXR). To investigate this, cholestasis was induced in both wild-type (C57BL/6N) mice and FXR knockout (FXR-null) mice through administration of rifampicin (200 mg/kg) via gavage for 7 consecutive days. Compared with C57BL/6N mice, FXR-null mice exhibited more severe liver injury after rifampicin administration, characterized by enlarged liver size, elevated transaminases, and increased inflammation. Moreover, under rifampicin treatment, FXR knockout impairs lipid secretion and exacerbates hepatic steatosis. Significantly, the expression of metabolism molecules BSEP increased, while NTCP and CYP7A1 decreased following rifampicin administration in C57BL/6N mice, whereas these changes were absent in FXR knockout mice. Furthermore, rifampicin treatment in both C57BL/6N and FXR-null mice was associated with elevated c-Jun N-terminal kinase phosphorylation (p-JNK) levels, with a more pronounced elevation in FXR-null mice. Our study suggests that rifampicin-induced liver injury, steatosis, and cholestasis are associated with FXR dysfunction and altered bile acid metabolism, and that the JNK signaling pathway is partially implicated in this injury. Based on these results, we propose that FXR might be a novel therapeutic target for addressing drug-induced liver injury.

A novel chemically engineered multifunctional statin conjugate as self-assembled nanoparticles inhibiting bile acid transporters.

Statins are widely used to treat hyperlipidemia; however, their mechanism-inhibiting cholesterol production without promoting its utilization-causes problems, such as inducing diabetes. In our research, we develop, for the first time, a chemically engineered statin conjugate that not only inhibits cholesterol production but also enhances its consumption through its multifunctional properties. The novel rosuvastatin (RO) and ursodeoxycholic acid (UDCA) conjugate (ROUA) is designed to bind to and inhibit the core of the apical sodium-dependent bile acid transporter (ASBT), effectively blocking ASBT's function in the small intestine, maintaining the effect of rosuvastatin. Consequently, ROUA not only preserves the cholesterol-lowering function of statins but also prevents the reabsorption of bile acids, thereby increasing cholesterol consumption. Additionally, ROUA's ability to self-assemble into nanoparticles in saline-attributable to its multiple hydroxyl groups and hydrophobic nature-suggests its potential for a prolonged presence in the body. The oral administration of ROUA nanoparticles in animal models using a high-fat or high-fat/high-fructose diet shows remarkable therapeutic efficacy in fatty liver, with low systemic toxicity. This innovative self-assembling multifunctional molecule design approach, which boosts a variety of therapeutic effects while minimizing toxicity, offers a significant contribution to the advancement of drug development.

The renal apical sodium-dependent bile acid transporter expression rescue attenuates renal damage in diabetic nephropathy via farnesoid X receptor activation.

AIM: Bile acids (BA) function as signalling molecules regulating glucose-lipid homeostasis and energy expenditure. However, the expression of the apical sodium-dependent bile acid transporter (ASBT) in the kidney, responsible for renal BA reabsorption, is downregulated in patients with diabetic kidney disease (DKD). Using the db/db mouse model of DKD, this study aimed to investigate the effects of rescuing ASBT expression via adeno-associated virus-mediated delivery of ASBT (AAVASBT) on kidney protection. METHODS: Six-week-old male db/db mice received an intraparenchymal injection of AAVASBT at a dose of 1 × 1011 viral genomes (vg)/animal and were subsequently fed a chow diet for 2 weeks. Male db/m mice served as controls. For drug treatment, daily intraperitoneal (i.p.) injections of the farnesoid X receptor (FXR) antagonist guggulsterone (GS, 10 mg/kg) were administered one day after initiating the experiment. RESULTS: AAVASBT treatment rescued renal ASBT expression and reduced the urinary BA output in db/db mice. AAVASBT treatment activated kidney mitochondrial biogenesis and ameliorated renal impairment associated with diabetes by activating FXR. In addition, the injection of FXR antagonist GS in DKD mice would reverse these beneficial effects by AAVASBT treatment. CONCLUSION: Our work indicated that restoring renal ASBT expression slowed the course of DKD via activating FXR. FXR activation stimulates mitochondrial biogenesis while reducing renal oxidative stress and lipid build up, indicating FXR activation's crucial role in preventing DKD. These findings further suggest that the maintenance of renal BA reabsorption could be a viable treatment for DKD.

Bile acid-microbiota crosstalk in hepatitis B virus infection.

Hepatitis B virus (HBV) is a hepatotropic non-cytopathic virus characterized by liver-specific gene expression. HBV infection highjacks bile acid metabolism, notably impairing bile acid uptake via sodium taurocholate cotransporting polypeptide (NTCP), which is a functional receptor for HBV entry. Concurrently, HBV infection induces changes in bile acid synthesis and the size of the bile acid pool. Conversely, bile acid facilitates HBV replication and expression through the signaling molecule farnesoid X receptor (FXR), a nuclear receptor activated by bile acid. However, in HepaRG cells and primary hepatocytes, FXR agonists suppress HBV RNA expression and the synthesis and secretion of DNA. In the gut, the size and composition of the bile acid pool significantly influence the gut microbiota. In turn, the gut microbiota impacts bile acid metabolism and innate immunity, potentially promoting HBV clearance. Thus, the bile acid-gut microbiota axis represents a complex and evolving relationship in the context of HBV infection. This review explores the interplay between bile acid and gut microbiota in HBV infection and discusses the development of HBV entry inhibitors targeting NTCP.

Increased intestinal bile acid absorption contributes to age-related cognitive impairment.

Cognitive impairment in the elderly is associated with alterations in bile acid (BA) metabolism. In this study, we observe elevated levels of serum conjugated primary bile acids (CPBAs) and ammonia in elderly individuals, mild cognitive impairment, Alzheimer's disease, and aging rodents, with a more pronounced change in females. These changes are correlated with increased expression of the ileal apical sodium-bile acid transporter (ASBT), hippocampal synapse loss, and elevated brain CPBA and ammonia levels in rodents. In vitro experiments confirm that a CPBA, taurocholic acid, and ammonia induced synaptic loss. Manipulating intestinal BA transport using ASBT activators or inhibitors demonstrates the impact on brain CPBA and ammonia levels as well as cognitive decline in rodents. Additionally, administration of an intestinal BA sequestrant, cholestyramine, alleviates cognitive impairment, normalizing CPBAs and ammonia in aging mice. These findings highlight the potential of targeting intestinal BA absorption as a therapeutic strategy for age-related cognitive impairment.

Puerarin Modulates Hepatic Farnesoid X Receptor and Gut Microbiota in High-Fat Diet-Induced Obese Mice.

Obesity is associated with alterations in lipid metabolism and gut microbiota dysbiosis. This study investigated the effects of puerarin, a bioactive isoflavone, on lipid metabolism disorders and gut microbiota in high-fat diet (HFD)-induced obese mice. Supplementation with puerarin reduced plasma alanine aminotransferase, liver triglyceride, liver free fatty acid (FFA), and improved gut microbiota dysbiosis in obese mice. Puerarin's beneficial metabolic effects were attenuated when farnesoid X receptor (FXR) was antagonized, suggesting FXR-mediated mechanisms. In hepatocytes, puerarin ameliorated high FFA-induced sterol regulatory element-binding protein (SREBP) 1 signaling, inflammation, and mitochondrial dysfunction in an FXR-dependent manner. In obese mice, puerarin reduced liver damage, regulated hepatic lipogenesis, decreased inflammation, improved mitochondrial function, and modulated mitophagy and ubiquitin-proteasome pathways, but was less effective in FXR knockout mice. Puerarin upregulated hepatic expression of FXR, bile salt export pump (BSEP), and downregulated cytochrome P450 7A1 (CYP7A1) and sodium taurocholate transporter (NTCP), indicating modulation of bile acid synthesis and transport. Puerarin also restored gut microbial diversity, the Firmicutes/Bacteroidetes ratio, and the abundance of Clostridium celatum and Akkermansia muciniphila. This study demonstrates that puerarin effectively ameliorates metabolic disturbances and gut microbiota dysbiosis in obese mice, predominantly through FXR-dependent pathways. These findings underscore puerarin's potential as a therapeutic agent for managing obesity and enhancing gut health, highlighting its dual role in improving metabolic functions and modulating microbial communities.

Joint host-pathogen genomic analysis identifies hepatitis B virus mutations associated with human NTCP and HLA class I variation.

Evolutionary changes in the hepatitis B virus (HBV) genome could reflect its adaptation to host-induced selective pressure. Leveraging paired human exome and ultra-deep HBV genome-sequencing data from 567 affected individuals with chronic hepatitis B, we comprehensively searched for the signatures of this evolutionary process by conducting "genome-to-genome" association tests between all human genetic variants and viral mutations. We identified significant associations between an East Asian-specific missense variant in the gene encoding the HBV entry receptor NTCP (rs2296651, NTCP S267F) and mutations within the receptor-binding region of HBV preS1. Through in silico modeling and in vitro preS1-NTCP binding assays, we observed that the associated HBV mutations are in proximity to the NTCP variant when bound and together partially increase binding affinity to NTCP S267F. Furthermore, we identified significant associations between HLA-A variation and viral mutations in HLA-A-restricted T cell epitopes. We used in silico binding prediction tools to evaluate the impact of the associated HBV mutations on HLA presentation and observed that mutations that result in weaker binding affinities to their cognate HLA alleles were enriched. Overall, our results suggest the emergence of HBV escape mutations that might alter the interaction between HBV PreS1 and its cellular receptor NTCP during viral entry into hepatocytes and confirm the role of HLA class I restriction in inducing HBV epitope variations.

Synthesis and evaluation of pentacyclic triterpenoids conjugates as novel HBV entry inhibitors targeting NTCP receptor.

Chronic liver diseases caused by hepatitis B virus (HBV) are the accepted main cause leading to liver cirrhosis, hepatic fibrosis, and hepatic carcinoma. Sodium taurocholate cotransporting polypeptide (NTCP), a specific membrane receptor of hepatocytes for triggering HBV infection, is a promising target against HBV entry. In this study, pentacyclic triterpenoids (PTs) including glycyrrhetinic acid (GA), oleanolic acid (OA), ursolic acid (UA) and betulinic acid (BA) were modified via molecular hybridization with podophyllotoxin respectively, and resulted in thirty-two novel conjugates. The anti-HBV activities of conjugates were evaluated in HepG2.2.15 cells. The results showed that 66% of the conjugates exhibited lower toxicity to the host cells and had significant inhibitory effects on the two HBV antigens, especially HBsAg. Notably, the compounds BA-PPT1, BA-PPT3, BA-PPT4, and UA-PPT3 not only inhibited the secretion of HBsAg but also suppressed HBV DNA replication. A significant difference in the binding of active conjugates to NTCP compared to the HBV PreS1 antigen was observed by SPR assays. The mechanism of action was found to be the competitive binding of these compounds to the NTCP 157-165 epitopes, blocking HBV entry into host cells. Molecular docking results indicated that BA-PPT3 interacted with the amino acid residues of the target protein mainly through π-cation, hydrogen bond and hydrophobic interaction, suggesting its potential as a promising HBV entry inhibitor targeting the NTCP receptor.

Evolutionary analysis of SLC10 family members and insights into function and expression regulation of lamprey NTCP.

The Na ( +)-taurocholate cotransporting polypeptide (NTCP) is a member of the solute carrier family 10 (SLC10), which consists of 7 members (SLC10a1-SLC10a7). NTCP is a transporter localized to the basolateral membrane of hepatocytes and is primarily responsible for the absorption of bile acids. Although mammalian NTCP has been extensively studied, little is known about the lamprey NTCP (L-NTCP). Here we show that L-NTCP follows the biological evolutionary history of vertebrates, with conserved domain, motif, and similar tertiary structure to higher vertebrates. L-NTCP is localized to the cell surface of lamprey primary hepatocytes by immunofluorescence analysis. HepG2 cells overexpressing L-NTCP also showed the distribution of L-NTCP on the cell surface. The expression profile of L-NTCP showed that the expression of NTCP is highest in lamprey liver tissue. L-NTCP also has the ability to transport bile acids, consistent with its higher vertebrate orthologs. Finally, using a farnesoid X receptor (FXR) antagonist, RT-qPCR and flow cytometry results showed that L-NTCP is negatively regulated by the nuclear receptor FXR. This study is important for understanding the adaptive mechanisms of bile acid metabolism after lamprey biliary atresia based on understanding the origin, evolution, expression profile, biological function, and expression regulation of L-NTCP.

Design and development of novel self-assembled catechol-modified bile acid conjugates as pH-responsive apical sodium-dependent bile acid transporter targeting nanoparticles.

Catechol-based biomaterials demonstrate biocompatibility, making them suitable for a wide range of therapeutic applications when integrated into various molecular frameworks. However, the development of orally available catechol-based biomaterials has been hindered by significant pH variations and complex interactions in the gastrointestinal (GI) tract. In this study, we introduce a novel catechol-modified bile acid (CMBA), which is synthesized by anchoring the FDA-approved drug, ursodeoxycholic acid to the neurotransmitter dopamine. This modification could form a new apical sodium-dependent bile acid transporter (ASBT) inhibitor (ASBTi) due to the bile acid moiety. The computational analysis using the TRAnsient Pockets in Proteins (TRAPP) module, coupled with MD simulations, revealed that CMBA exhibits a strong binding affinity at residues 51-55 of ASBT with a low inhibitory constant (Ki) value. Notably, in slightly alkaline biological conditions, CMBA molecules self-assemble into carrier-free nanoparticles with an average size of 240.2 ± 44.2 nm, while maintaining their ability to bind with ASBT. When administered orally, CMBA accumulates in the ileum and liver over 24 h, exhibiting significant therapeutic effects on bile acid (BA) metabolism in a high-fat diet (HFD)-fed mouse model. This study underscores the therapeutic potential of the newly developed catechol-based, pH-responsive ASBT-inhibiting nanoparticles presenting a promising avenue for advancing therapy.

Molecular mechanisms of Na+-driven bile acid transport in human NTCP.

Human Na+ taurocholate co-transporting protein (hNTCP) is a key bile salt transporter to maintain enterohepatic circulation and is responsible for the recognition of hepatitis B and D viruses. Despite landmark cryoelectron microscopy studies revealing open-pore and inward-facing states of hNTCP stabilized by antibodies, the transport mechanism remains largely unknown. To address this knowledge gap, we used molecular dynamics and enhanced sampling metadynamics simulations to elucidate the intrinsic mechanism of hNTCP-mediated taurocholate acid (TCA) transport driven by Na+ binding. We uncovered three TCA-binding modes, including one that closely matched the limited cryoelectron microscopy density observed in the open-pore hNTCP. We also captured several key hNTCP conformations in the substrate transport cycle, particularly including an outward-facing, substrate-bound state. Furthermore, we provided thermodynamic evidence supporting that changes in the Na+-binding state drive the TCA transport by exploiting the amphiphilic nature of the substrate and modulating the protein environment, thereby enabling the TCA molecule to flip through. Understanding these mechanistic details of Na+-driven bile acid transport may aid in the development of hNTCP-targeted therapies for liver diseases.

Hepatitis B virus-targeting sodium taurocholate cotransporting polypeptide mediates HBV infection and damage in human renal podocytes.

Hepatitis B virus (HBV) may directly infect human podocytes (HPCs). However, the mechanism of direct infection is unclear. We found that HPCs express sodium taurocholate cotransporting polypeptide (NTCP), a specific receptor for HBV entry into hepatocytes. Thus, we investigated whether NTCP mediates HBV infection and damage in HPCs and further clarified the specific mechanism. We constructed shRNA-NTCP1,2, shRNA-NC, WT-NTCP, and MUT-NTCP and transfected them into HPCs. HPCs were infected with HBV, and HBV infection markers were detected by enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR (RT-qPCR). The functional changes in HPCs were detected by Transwell migration and scratch assays, apoptosis was evaluated by flow cytometry (FCM), and podocytoskeletal proteins (nephrin, CD2AP, and synaptopodin) were determined by western blotting (WB). Compared with the control HPCs, HPCs infected with HBV showed increased levels of HBV infection markers and apoptosis along with decreased podocytoskeletal protein expressions, cell vitality, proliferation, and migration. Compared with the HPCs infected with HBV, the HPCs transfected with HBV + shRNA-NTCP, and HBV + MUT-NTCP showed decreased levels of HBV infection markers and apoptosis along with increased podocytoskeletal protein expressions, cell vitality, proliferation, and migration; the opposite effects were observed in the HPCs transfected with HBV + WT-NTCP. Overall, the changes to NTCP affected the susceptibility of HPCs to HBV and modulated HPC damage and repair. NTCP can mediate direct HBV infection and damage human podocytes, and the NTCP 157-165 locus is the main site of HBV entry. The findings provide a new target and theoretical basis for HBV-associated glomerulonephritis. IMPORTANCE: This study identified for the first time that sodium taurocholate cotransporting polypeptide (NTCP) can mediate HBV direct infection and damage to human podocytes, and the NTCP157-165 locus is the main HBV entry site. The findings provide theoretical support for the pathogenesis of direct infection of HBV with kidney tissue. The findings provide a new target and theoretical basis for the treatment of HBV-related glomerulonephritis (HBV-GN). Blocking NTCP is a new target for the treatment of HBV-GN. We found that tacrolimus, a calcineurin inhibitor that blocks NTCP, can effectively treat HBV-GN. This study also provides a theoretical basis for the effective and safe treatment of immunosuppressant tacrolimus for HBV-GN.

Clostridium scindens exacerbates experimental necrotizing enterocolitis via upregulation of the apical sodium-dependent bile acid transporter.

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in premature infants. Evidence indicates that bile acid homeostasis is disrupted during NEC: ileal bile acid levels are elevated in animals with experimental NEC, as is expression of the apical sodium-dependent bile acid transporter (Asbt). In addition, bile acids, which are synthesized in the liver, are extensively modified by the gut microbiome, including via the conversion of primary bile acids to more cytotoxic secondary forms. We hypothesized that the addition of bile acid-modifying bacteria would increase susceptibility to NEC in a neonatal rat model of the disease. The secondary bile acid-producing species Clostridium scindens exacerbated both incidence and severity of NEC. C. scindens upregulated the bile acid transporter Asbt and increased levels of intraenterocyte bile acids. Treatment with C. scindens also altered bile acid profiles and increased hydrophobicity of the ileal intracellular bile acid pool. The ability of C. scindens to enhance NEC requires bile acids, as pharmacological sequestration of ileal bile acids protects animals from developing disease. These findings indicate that bile acid-modifying bacteria can contribute to NEC pathology and provide additional evidence for the role of bile acids in the pathophysiology of experimental NEC.NEW & NOTEWORTHY Necrotizing enterocolitis (NEC), a life-threatening gastrointestinal emergency in premature infants, is characterized by dysregulation of bile acid homeostasis. We demonstrate that administering the secondary bile acid-producing bacterium Clostridium scindens enhances NEC in a neonatal rat model of the disease. C. scindens-enhanced NEC is dependent on bile acids and driven by upregulation of the ileal bile acid transporter Asbt. This is the first report of bile acid-modifying bacteria exacerbating experimental NEC pathology.