Why highly effective drugs are not enough: the need for an affordable solution to eliminating HCV

Prospects for preventing cancer with anti-microbial prophylactic vaccines

Vaccines against cancer-causing microbes could potentially prevent 15% of cancers worldwide and thereby address global disparities in cancer control. To reach this potential, the established hepatitis B virus and human papillomavirus vaccines must be more widely implemented, and effective vaccines against Epstein-Barr virus, hepatitis C virus, and Helicobacter pylori must be developed.

Total Joint Arthroplasty Should Not Be Delayed in Hepatitis C Patients After Successful Treatment Achieving a Sustained Viral Load

Background

Preoperative treatment recommendations and optimal time to perform total joint arthroplasty (TJA) in patients with hepatitis C virus after treatment completion for achieving best outcomes have not been elucidated. We aim to determine (1) if undetectable viral load (UVL) prior to TJA leads to decreased postoperative complication rates, specifically periprosthetic joint infection (PJI), and (2) if delaying TJA after treatment completion has benefit in decreasing PJI.

Methods

A retrospective review of all hepatitis C virus patients undergoing TJA at 3 academic tertiary care centers was conducted. A total of 270 TJAs performed from 2005 to 2019 were included, 125 with positive viral load at the time of surgery. The duration from completion of treatment regimen to TJA was recorded for the UVL cohort. The primary study outcome was PJI at 1-year follow-up. Secondary outcomes included in-hospital complications, mechanical revision TJA rates, and optimal time to TJA upon completion of treatment.

Results

Patients with positive viral load at the time of TJA had longer length of stay (3.9 vs 2.9 days, P < .0001) and a higher PJI rate at 1 year postoperatively (9% vs 2%, P = .02) than UVL patients. There was no difference of in-hospital complications or revision rates for mechanical etiologies. Delaying TJA after achieving a sustained virologic response did not impact PJI rates.

Conclusions

Sustained UVL prior to TJA is critical to minimize PJI irrespective of the treatment regimen utilized. Surgery can be performed with lower complication rates any time after achieving sustained virologic response.

Level of Evidence

Level III, prognostic retrospective cohort study.

N-Substituted Valiolamine Derivatives as Potent Inhibitors of Endoplasmic Reticulum α-Glucosidases I and II with Antiviral Activity

Most enveloped viruses rely on the host cell endoplasmic reticulum (ER) quality control (QC) machinery for proper folding of glycoproteins. The key ER α-glucosidases (α-Glu) I and II of the ERQC machinery are attractive targets for developing broad-spectrum antivirals. Iminosugars based on deoxynojirimycin have been extensively studied as ER α-glucosidase inhibitors; however, other glycomimetic compounds are less established. Accordingly, we synthesized a series of N-substituted derivatives of valiolamine, the iminosugar scaffold of type 2 diabetes drug voglibose. To understand the basis for up to 100,000-fold improved inhibitory potency, we determined high-resolution crystal structures of mouse ER α-GluII in complex with valiolamine and 10 derivatives. The structures revealed extensive interactions with all four α-GluII subsites. We further showed that N-substituted valiolamines were active against dengue virus and SARS-CoV-2 in vitro. This study introduces valiolamine-based inhibitors of the ERQC machinery as candidates for developing potential broad-spectrum therapeutics against the existing and emerging viruses.

BacMam virus-based surface display for HCV E2 glycoprotein induces strong cross-neutralizing antibodies and cellular immune responses in vaccinated mice

Background

Despite recent advancements, limitations in the treatment and control of hepatitis C virus (HCV) infection reprioritized the studies for invention of an efficient HCV vaccine to elicit strong neutralizing antibodies (NAbs) and cellular responses.

Methods

Herein, we report molecular construction of a BacMam virus-based surface display for a subtype-1a HCV gpE2 (Bac-CMV-E2-gp64; Bac) that both expressed and displayed gpE2 in mammalian cells and bacouloviral envelope, respectively.

Results

Assessments by western blotting, Immunofluorescence and Immunogold-electron microscopy indicated the proper expression and incorporation in insect cell and baculovirus envelope, respectively. Mice immunized in three different prime-boost immunization groups of: Bac/Bac, Bac/Pro (bacoulovirus-derived gpE2) and Bac/DNA (plasmid DNA (pCDNA)-encoding gpE2) developed high levels of IgG and IFN-γ (highest for Bac/Bac group) indicating the induction of both humeral and cellular immune responses. Calculation of the IgG2a/IgG1 and IFN-γ/IL-4 ratios indicated a Th1 polarization of immune responses in the Bac/Bac and Bac/DNA groups but a balanced Th1-Th2 phenotype in the Bac/Pro group. Sera of the mice in the Bac/Bac group provided the highest percentage of cross-NAbs against a subtype-2a HCVcc (JFH1) compared to Bac/Pro and Bac/DNA groups (62% versus 41% and 6%).

Conclusions

Results indicated that BacMam virus-based surface display for gpE2 might act as both subunit and DNA vaccine and offers a promising strategy for development of HCV vaccine for concurrent induction of strong humoral and cellular immune responses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13027-021-00407-x.

Structure-Based and Rational Design of a Hepatitis C Virus Vaccine

A hepatitis C virus (HCV) vaccine is a critical yet unfulfilled step in addressing the global disease burden of HCV. While decades of research have led to numerous clinical and pre-clinical vaccine candidates, these efforts have been hindered by factors including HCV antigenic variability and immune evasion. Structure-based and rational vaccine design approaches have capitalized on insights regarding the immune response to HCV and the structures of antibody-bound envelope glycoproteins. Despite successes with other viruses, designing an immunogen based on HCV glycoproteins that can elicit broadly protective immunity against HCV infection is an ongoing challenge. Here, we describe HCV vaccine design approaches where immunogens were selected and optimized through analysis of available structures, identification of conserved epitopes targeted by neutralizing antibodies, or both. Several designs have elicited immune responses against HCV in vivo, revealing correlates of HCV antigen immunogenicity and breadth of induced responses. Recent studies have elucidated the functional, dynamic and immunological features of key regions of the viral envelope glycoproteins, which can inform next-generation immunogen design efforts. These insights and design strategies represent promising pathways to HCV vaccine development, which can be further informed by successful immunogen designs generated for other viruses.

Canola oilseed- and Escherichia coli- derived hepatitis C virus (HCV) core proteins adjuvanted with oil bodies, induced robust Th1-oriented immune responses in immunized mice

Induction of broad Th1 cellular immune responses and cytokines is crucial characteristics for vaccines against intracellular infections such as hepatitis C virus (HCV). Plants (especially oilseed tissues) and plant-immunomodulators (like oil bodies) offer cost-effective and scalable possibilities for the production of immunologically relevant and safe vaccine antigens and adjuvants, respectively. Herein, we provide data of the murine immunization by transgenic canola oilseed-derived HCV core protein (HCVcp) soluble extract (TSE) and Escherichia coli- derived rHCVcp in combination with Canola oil bodies (oil) compared to that of the Freund's (FA) adjuvant. Mice immunized by TSE+ oil developed both strong humeral (IgG) and Th1-biased cellular responses, manifested by high levels of IFN-γ and lower IgG1/IgG2a ratio and IL-4 secretion. Results of the intracellular cytokine staining indicated that TSE+ oil immunization in mice triggered both CD4⁺ and CD8⁺ T cells to release IFN-γ, while CD4⁺ cells were mostly triggered when FA was used. Analyses by qRT-PCR indicated that a combination of rHCVcp/TSE with oil body induced high levels of IL-10 cytokines compared to that of the FA adjuvant. These characteristics are important properties for the design of an HCV vaccine candidate and indicate the potential of Canola-derived antigen and oil bodies in addressing these concerns.

Prevalence of HCV resistance-associated substitutions among treatment-failure patients receiving direct-acting antiviral agents

Direct-acting antiviral (DAA) failure, which is mainly associated with the selection of resistance-associated substitutions (RASs), is not rare in HCV treatment. RAS data collected from published literature and RAS prevalence were integrated using meta-analysis. DAA-failure-associated RASs were identified by comparing their prevalence between DAA-failure and DAA-naïve patients. Prevalences of emerging RASs that occurred during treatment were also estimated. A total of 2932 DAA-naïve patients and 1466 DAA-failure patients were included. Significant differences in the prevalence of RASs were found in 76 scenarios that involved 34 RASs (11 in NS3, 18 in NS5A and 5 in NS5B), 4 genotypes (GTs) (GT1a, GT1b and GT3-4) and 14 DAAs (6 NS3 protease inhibitors [PIs], 6 NS5A inhibitors and 2 NS5B inhibitors). For NS3, the DAA-failure-associated RASs included V36L, Y56H, Q80K/R, R155K, A156T and D168A/E/L/T/V/Y. Substitutions at R155 and D168 were dominant for most NS3 PIs. For NS5A, DAA-failure-associated RASs included K24R, Q30R, L31M, and P32L in GT1a; R30Q/H, L31F/I/M/V, P58S, and Y93H in GT1b; A30K, L31M and Y93H in GT3; and M31V and Y93H in GT4. Y93H was the most prevalent RAS for NS5A inhibitors. DAA-failure-associated RASs were found at only five positions in NS5B. The majority of DAA-failure patients relapsed. A significant difference was detected for only four RAS sites between relapse patients and nonresponse/breakthrough patients. The RAS prevalence in DAA-failure patients varied among the HCV GTs and DAA regimens. The identified treatment-selected resistance patterns for broadly used DAA regimens will enable the selection of optimized retreatment options.

Junctional and somatic hypermutation-induced CX4C motif is critical for the recognition of a highly conserved epitope on HCV E2 by a human broadly neutralizing antibody

Induction of broadly neutralizing monoclonal antibodies (bNAbs) that bind to the viral envelope glycoproteins is a major goal of hepatitis C virus (HCV) vaccine research. The study of bNAbs arising in natural infection is essential in this endeavor. We generated a human antibody, 8D6, recognizing the E2 protein of HCV isolated from a chronic hepatitis C patient. This antibody shows broadly neutralizing activity, which covers a pan-genotypic panel of cell culture-derived HCV virions (HCVcc). Functional and epitope analyses demonstrated that 8D6 can block the interaction between E2 and CD81 by targeting a highly conserved epitope on E2. We describe how the 8D6 lineage evolved via somatic hypermutation to achieve broad neutralization. We found that the V(D)J recombination-generated junctional and somatic hypermutation-induced disulfide bridge (C-C) motif in the CDRH3 is critical for the broad neutralization and binding activity of 8D6. This motif is conserved among a series of broadly neutralizing HCV antibodies, indicating a common binding model. Next, the 8D6 inferred germline (iGL) was reconstructed and tested for its binding affinity and neutralization activity. Interestingly, 8D6 iGL-mediated relatively strong inhibition of the 1b genotype PR79L9 strain, suggesting that PR79L9 may serve as a potential natural viral strain that provides E2 sequences that induce bNAbs. Overall, our detailed epitope mapping and genetic studies of the HCV E2-specific mAb 8D6 have allowed for further refinement of antigenic sites on E2 and reveal a new mechanism to generate a functional CDRH3, while its iGL can serve as a probe to identify potential HCV vaccine strains.

STAT3 signaling pathway plays importantly genetic and functional roles in HCV infection

Background

Hepatitis C virus (HCV) infection is an extensive health problem, which leads to serious liver diseases. Host genetic polymorphisms were associated with HCV infection, progression, and treatment effect of patients. Signal transducers and activators of transcription 3 (STAT3) signaling pathway was important to HCV infection, but no genetic association was studied between STAT3 signaling pathway and HCV infection.

Methods

To investigate the genetic and functional roles of the STAT3 signaling pathway, we collected 394 HCV patients and 395 normal controls to genotype 25 signal nucleotide polymorphisms (SNPs) of six genes (Interleukin 6 [IL6, OMIM 147620], Interleukin 6 receptor [IL6R, OMIM 147880], Hepatocyte nuclear factor 1 alpha [HNF1A, OMIM 142410], Hepatocyte nuclear factor 4 alpha [HNF4A, OMIM 600281], STAT3 [OMIM 102582], and ATP binding cassette subfamily C member 2 [ABCC2, OMIM 601107]). Then expression level of these genes were analyzed in HCV infected cells with or without IL6 transfection.

Results

Our results identified that the SNPs in STAT3 signaling pathway were associated with HCV infection or biochemical features of Yunnan HCV patients. Genotype AA of rs4075015 (IL6R) and GG of rs3212172 (HNF4A) increased the risk of HCV infection (p = 0.024 and 0.029), but the genotype AA of rs7553796 (IL6R) played a protective role in HCV infection (p = 0.0008). High‐density lipoprotein cholesterol (HDL‐C) and Glutamyl transpeptidase (GGT) level were associated with genotypes of rs4845617 (IL6R, p = 0.045) and rs1053023 (STAT3, p = 0.034), respectively. Cell assays suggested that IL6 transfection could suppress HCV proliferation. RNA and protein levels of the IL6R, HNF1A, STAT3, and ABCC2 genes significantly increased after HCV infection.

Conclusion

We identified STAT3 signaling pathway influenced HCV infection and biochemical characteristics of HCV patients through genetic and functional aspects.

Status of Direct-Acting Antiviral Therapy for Hepatitis C Virus Infection and Remaining Challenges

Chronic infection with hepatitis C virus is a major cause of liver disease and hepatocellular carcinoma worldwide. After the discovery of hepatitis C virus 3 decades ago, the identification of the structure of the viral proteins, combined with high-throughput replicon models, enabled the discovery and development of direct-acting antivirals. These agents have revolutionized patient care, with cure rates of more than 90%. We review the status of direct-acting antiviral therapies for hepatitis C virus infection and discuss remaining challenges. We highlight licensed compounds, discuss the potential to shorten therapy even further, and review different options for treatment failure and resistance. We also provide an overview of clinical experience with generic agents and evidence for their efficacy. Finally, we discuss the need for new drugs and outline promising targets for future therapies.

Treatment for Chronic Hepatitis C Prior to Total Hip Arthroplasty Significantly Reduces Periprosthetic Joint Infection

BACKGROUND

Patients with chronic hepatitis C (HCV) have had extremely high complication rates after total hip arthroplasty (THA). We sought to compare perioperative complication rates between untreated and treated HCV in THA patients and to compare these rates between patients treated with 2 different therapies (interferon vs direct antiviral agents).

METHODS

A multicenter retrospective database query was used to identify patients diagnosed with HCV who underwent THA between 2006 and 2016. All patients (n = 105) identified were included and divided into 2 groups: untreated (n = 63) and treated (n = 42) HCV; treated patients were further subdivided into those receiving interferon (n = 16) or direct antiviral agent therapies (n = 26). Comparisons between the treated and untreated groups were made with respect to demographic data, comorbidities, preoperative viral load, Model for End-Stage Liver Disease score, and all surgical and medical complications; a subgroup analysis of the treated patients was also performed. Separate independent t-tests or Mann-Whitney U tests were conducted for continuous variables. Categorical variables were compared using the chi-squared test of independence.

RESULTS

A greater number of untreated patients were human immunodeficiency virus infected (P = .01), while a reduced number of treated patients were either former or current smokers (P = .004). The untreated group had greater surgical complication rates (25.4% vs 4.8%; P = .007), with a higher rate of periprosthetic joint infection (14.3% vs 0%, P = .01). For treated patients, no differences were observed between treatment types for postsurgical complications.

CONCLUSION

Treatment for HCV prior to THA appears to be associated to fewer postoperative complications, primarily periprosthetic joint infection. Although further investigation is warranted, strong consideration should be given to treating patients for HCV prior to elective THA.

Antibody Repertoire Analysis of Hepatitis C Virus Infections Identifies Immune Signatures Associated With Spontaneous Clearance

Hepatitis C virus (HCV) is a major public health concern, with over 70 million people infected worldwide, who are at risk for developing life-threatening liver disease. No vaccine is available, and immunity against the virus is not well-understood. Following the acute stage, HCV usually causes chronic infections. However, ~30% of infected individuals spontaneously clear the virus. Therefore, using HCV as a model for comparing immune responses between spontaneous clearer (SC) and chronically infected (CI) individuals may empower the identification of mechanisms governing viral infection outcomes. Here, we provide the first in-depth analysis of adaptive immune receptor repertoires in individuals with current or past HCV infection. We demonstrate that SC individuals, in contrast to CI patients, develop clusters of antibodies with distinct properties. These antibodies' characteristics were used in a machine learning framework to accurately predict infection outcome. Using combinatorial antibody phage display library technology, we identified HCV-specific antibody sequences. By integrating these data with the repertoire analysis, we constructed two antibodies characterized by high neutralization breadth, which are associated with clearance. This study provides insight into the nature of effective immune response against HCV and demonstrates an innovative approach for constructing antibodies correlating with successful infection clearance. It may have clinical implications for prognosis of the future status of infection, and the design of effective immunotherapies and a vaccine for HCV.

Antifibrotic Activity and In Ovo Toxicity Study of Liver-Targeted Curcumin-Gold Nanoparticle

Conjugation of curcumin and gold with green chemistry is an approach to improve the effectiveness of curcumin as anti-fibrosis. In this work, curcumin and gold were conjugated to deliver curcumin to the liver. Curcumin-gold nanoparticles (cAuNPs) were prepared by varying curcumin pH and concentration. The successful of cAuNPs formation were identified by using UV-visible and FTIR spectrophotometers. The particle size and morphology were analyzed using particle size analyzer and cryo-TEM respectively. In vitro antioxidant assay was performed to determine the curcumin activity after conjugation. Physical and chemical stabilities of cAuNPs were studied for one month at 5 °C, 25 °C, and 40 °C. Furthermore, the cAuNPs activity to modulate early marker of fibrosis was tested on NIH/3T3 cells. The optimum condition for cAuNPs synthesis was by using 1.5 mM curcumin at pH 9.3. As compared to free curcumin, cAuNPs showed higher antioxidant activity and maintained the nanosize after stored for one month. In line with the antioxidant activity, cAuNPs 0.25–1 μg/mL reduced the collagen production by NIH/3T3 cells. More importantly, cAuNPs did not demonstrate any effect on the development of chicken embryo. Taken together, the attachment of gold to curcumin in the form of cAuNPs is promising for curcumin targeting to treat hepatic fibrosis.