It is the scientific basis of precision medicine to study all of the targets of drugs based on the interaction between drugs and proteins. It is worth paying attention to unknown proteins that interact with drugs to find new targets for the design of new drugs. Herein, we developed a protein profiling strategy based on drug-protein interactions and drug-modified magnetic nanoparticles and took hepatitis C virus (HCV) and its corresponding drug sofosbuvir (SOF) as an example. A SOF-modified magnetic separation medium (Fe3O4@POSS@SOF) was prepared, and a gradient elution strategy was employed and optimized to profile specific proteins interacted with SOF. A series of proteomic analyses were performed to profile proteins based on SOF-protein interactions (SPIs) in the serum of HCV patients to evaluate the specificity of the profiling strategy. As a result, five proteins were profiled with strong SPIs and exhibited high relevance with liver tissue, which were potentially new drug targets. Among them, HSP60 was used to confirm the highly specific interactions between the SOF and its binding proteins by Western blotting analysis. Besides, 124 and 29 differential proteins were profiled by SOF material from three HCV patient serum and pooled 20 HCV patient serum, respectively, by comparing with healthy human serum. In comparison with those profiled by the polyhedral oligomeric silsesquioxane (POSS) material, differential proteins profiled by the SOF material were highly associated with liver diseases through GO analysis and pathway analysis. Furthermore, four common differential proteins profiled by SOF material but not by POSS material were found to be identical and expressed consistently in both pooled serum samples and independent serum samples, which might potentially be biomarkers of HCV infection. Taken together, our study proposes a highly specific protein profiling strategy to display distinctive proteomic profiles, providing a novel idea for drug design and development.

Current management of HCV infection is based on Direct-Acting Antiviral Drugs (DAAs). However, resistance-associated mutations, especially in the NS3 and NS5B regions are gradually decreasing the efficacy of DAAs. Among the most effective HCV NS3/4A protease drugs, Sofosbuvir also develops resistance due to mutations in the NS3 and NS5B regions. Four mutations at positions A156Y, L36P, Q41H, and Q80K are classified as high-level resistance mutations. The resistance mechanism of HCV NS3/4A protease toward Sofosbuvir caused by these mutations is still unclear, as there is less information available regarding the structural and functional effects of the mutations against Sofosbuvir. In this work, we combined molecular dynamics simulation, molecular mechanics/Generalized-Born surface area calculation, principal component analysis, and free energy landscape analysis to explore the resistance mechanism of HCV NS3/4A protease due to these mutations, as well as compare interaction changes in wild-type. Subsequently, we identified that the mutant form of HCV NS3/4A protease affects the activity of Sofosbuvir. In this study, the resistance mechanism of Sofosbuvir at the atomic level is proposed. The proposed drug-resistance mechanism will provide valuable guidance for the design of HCV drugs.

BACKGROUND: Sofosbuvir/Velpatasvir (Epclusa, ECS) is the first pan-genotype direct-acting antiviral agent (DAA) for hepatitis C virus (HCV) infection, and Danoprevir (DNV) is the first DAA developed by a Chinese local enterprise, which is suitable for combined use with other drugs to treat genotype 1b chronic hepatitis C. However, previous reports have never compared the real-world data of ECS and DNV.
METHODS: 178 chronic hepatitis C patients were retrospectively recruited, and 94cases were accepted with Sofosbuvir/Velpatasvir ± Ribavirin (ECS group), and others (n = 84 treated with DNV combination therapy (DNV group). The HCV genotype, virological response, adverse effects and some laboratory biochemical indexes were contrasted between above two groups in the real world study.
RESULTS: DNV group had significantly lower level of alpha-fetoprotein (AFP), lower rates of decompensated cirrhosis ( P < 0.05). ECS group possessed more 6a (31.91% vs.13.10%) while DNV group was provided with more 1b (48.81% vs. 22.34%) patients. Significantly poor liver function was detected in ECS group at 4-week treatment (ALT and AST) and 12-week follow-up (AST) (all P < 0.05). The SVR12 undetectable rates of both groups were 100%, and no serious event was observed during the treatment and follow-up in both groups.
CONCLUSIONS: In this retrospective real-world study, the efficacy of DNV combined therapy is similar to Sofosbuvir/Velpatasvir ± Ribavirin for chronic HCV infection, and the safety is comparable. DNV based therapy is a promising regimen for chronic hepatitis C.

BACKGROUND: Both European Association for the Study of the Liver (EASL) and American Association for the Study of Liver Diseases and the Infectious Diseases Society of America (AASLD-IDSA) guidelines recommend simplified hepatitis C virus (HCV) treatment with pan-genotypic sofosbuvir/velpatasvir or glecaprevir/pibrentasvir for eligible patients. This observational study used real-world data to assess these regimens\' safety in eligible patients and develop an algorithm to identify patients suitable for simplified treatment by non-specialists.
METHODS: 7,677 HCV-infected patients from Taiwan Hepatitis C Registry (TACR) who received at least one dose of sofosbuvir/velpatasvir or glecaprevir/pibrentasvir, and fulfilled the EASL/AASLD-IDSA criteria for simplified treatment were analyzed. Multivariate analysis was conducted on patient characteristics and safety data.
RESULTS: Overall, 92.8% (7,128/7,677) of patients achieved sustained virological response and only 1.9% (146/7,677) experienced Grades 2-4 laboratory abnormalities in key liver function parameters (alanine aminotransferase, aspartate aminotransferase, and total bilirubin), with only 18 patients (0.23%) experiencing Grades 3-4 abnormalities. Age > 70 years old, presence of hepatocellular carcinoma, total bilirubin > 1.2 mg/dL, estimated glomerular filtration rate < 60 mL/min/1.73 m2, and Fibrosis-4 > 3.25 were associated with higher risks of Grades 2-4 abnormalities. Patients with any of these had an odds of 4.53 times than that of those without in developing Grades 2-4 abnormalities (p < 0.01).
CONCLUSIONS: Real-world data from Taiwan confirmed that simplified HCV treatment for eligible patients with pan-genotypic regimens is effective and well tolerated. The TACR algorithm, developed based on this study\'s results, can further identify patients who can be safely managed by non-specialist care.

BACKGROUND: We describe a rare case of a 54-year-old male diagnosed with both ulcerative colitis (UC) and hepatitis C virus (HCV), posing clinical challenges.
METHODS: The patient showed worsened UC symptoms, leading to further evaluations.
METHODS: Dual diagnosis of UC and HCV was confirmed through endoscopy and serological tests, ruling out other hepatic causes. Interventions: Treatment involved methylprednisolone for UC and sofosbuvir/velpatasvir for HCV, with attention to drug interactions.
RESULTS: Significant improvement was observed in both UC symptoms and HCV viral load post-treatment.
CONCLUSIONS: This case underscores the need for nuanced treatment in managing concurrent UC and HCV, considering potential drug interactions and disease impacts.

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide. Among its 8 genotypes (GT), GT3 has a relatively lower sustained virological response to highly effective direct-acting antiviral agents (DAA). Sofosbuvir (SOF), an anti-NS5B polymerase inhibitor, is a core component of many anti-HCV DAA cocktail regimens, and its resistant mutations are rare in clinics because these mutations usually severely impair the NS5B polymerase activity, including a mutation S282T in NS5B, the most frequently reported SOF-resistant mutation. In this study, we selected SOF-resistant variants of a previously developed GT3 subgenomic replicon (PR87A7). Two mutations were identified in the viral genome of SOF-resistant PR87A7 variants, Q606R in nontargeted NS3 and S282T in targeted N5SB. We demonstrated that Q606R could rescue the replication defect of S282T in PR87A7, and the resulting double mutant confers the SOF resistance. Finally, we showed that NS3-606R could not compensate for the replication defect of S282T in other GTs. In conclusion, we identified a novel GT3-specific combination of two mutations that confers SOF resistance. Our result calls for attention to potential mutations that may arise in nontargeted viral proteins during the SOF-based DAA treatment of chronic HCV.

Cav1.2 channels play crucial roles in various neuronal and physiological processes. Here, we present cryo-EM structures of human Cav1.2, both in its apo form and in complex with several drugs, as well as the peptide neurotoxin calciseptine. Most structures, apo or bound to calciseptine, amlodipine, or a combination of amiodarone and sofosbuvir, exhibit a consistent inactivated conformation with a sealed gate, three up voltage-sensing domains (VSDs), and a down VSDII. Calciseptine sits on the shoulder of the pore domain, away from the permeation path. In contrast, when pinaverium bromide, an antispasmodic drug, is inserted into a cavity reminiscent of the IFM-binding site in Nav channels, a series of structural changes occur, including upward movement of VSDII coupled with dilation of the selectivity filter and its surrounding segments in repeat III. Meanwhile, S4-5III merges with S5III to become a single helix, resulting in a widened but still non-conductive intracellular gate.

Hepatitis C virus (HCV) infection remains a challenge to human public health despite the development of highly effective direct-acting antivirals (DAAs). Sofosbuvir (SOF), a key component in most DAA-based anti-HCV cocktail regimens, is a potent viral RNA polymerase (NS5B) inhibitor with a high barrier to drug resistance. The serine-to-threonine mutation at NS5B 282 (S282T) confers the SOF resistance, but severely impairs viral replication in most HCV genotypes (GTs) and cannot be stably maintained after the termination of the SOF-based therapies. In this study, we first developed a new HCV GT-6a subgenomic replicon PR58D6. Next, we selected SOF-resistant PR58D6 variants by culturing the replicon cells in the presence of SOF. Interestingly, unlike many other HCV replicons which require additional mutations to compensate for the S282T-inducing fitness loss, S282T alone in PR58D6 is genetically stable and confers the SOF resistance without significantly impairing viral replication. Furthermore, we showed that amino acid residue at NS5B 74 (R74) and 556 (D556) which are conserved in GT 6a HCV contribute to efficient replication of PR58D6 containing S282T. Finally, we showed that the G556D mutation in NS5B could rescue the replication deficiency of the S282T in JFH1, a GT-2a replicon. In conclusion, we showed that a novel GT-6a HCV replicon may easily render SOF resistance, which may call for attention to potential drug resistance during DAA therapies of HCV GT-6a patients.

我国鲜见使用直接抗病毒药物治疗6岁以下体质量< 17 kg慢性丙型肝炎儿童的临床报道。现报道1例基于体质量给予索磷布韦/维帕他韦联合利巴韦林治疗1例3岁、体质量< 17 kg的慢性丙型肝炎儿童，安全性良好且获得持续病毒学应答。.

BACKGROUND: Real-world data are scarce about the effectiveness and safety of sofosbuvir/velpatasvir/voxilaprevir (SOF/VEL/VOX) for retreating East Asian patients with hepatitis C virus (HCV) infection who previously received NS5A direct-acting antivirals (DAAs). We conducted a multicenter study to assess the performance of SOF/VEL/VOX in patients who were not responsive to prior NS5A inhibitors in Taiwan.
METHODS: Between September 2021 and May 2022, 107 patients who failed NS5A inhibitor-containing DAAs with SOF/VEL/VOX salvage therapy for 12 weeks were included at 16 academic centers. The sustained virologic response at off-treatment week 12 (SVR12) was assessed in the evaluable (EP) and per-protocol (PP) populations. The safety profiles were also reported.
RESULTS: All patients completed 12 weeks of treatment and achieved an end-of-treatment virologic response. The SVR12 rates were 97.2% (95% confidence interval (CI) 92.1-99.0%) and 100% (95% CI 96.4-100%) in EP and PP populations. Three (2.8%) patients were lost to off-treatment follow-up and did not meet SVR12 in the EP population. No baseline factors predicted SVR12. Two (1.9%) not-fatal serious adverse events (AE) occurred but were unrelated to SOF/VEL/VOX. Sixteen (15.0%) had grade 2 total bilirubin elevation, and three (2.8%) had grade 2 alanine transaminase (ALT) elevation. Thirteen (81.3%) of the 16 patients with grade 2 total bilirubin elevation had unconjugated hyperbilirubinemia. The estimated glomerular filtration rates (eGFR) were comparable between baseline and SVR12, regardless of baseline renal reserve.
CONCLUSIONS: SOF/VEL/VOX is highly efficacious and well-tolerated for East Asian HCV patients previously treated with NS5A inhibitor-containing DAAs.
BACKGROUND: The study was not a drug trial. There was no need for clinical trial registration.