Staphylokinase (Sak) holds promise for use in thrombolytic therapy for acute myocardial infarction. However, its immunogenicity is a major disadvantage under clinical conditions. PEGylation has become a sophisticated method to decrease that immunogenicity. In this report, according predicted epitope from the active center, five residues, including Gly79, Leu82, Lys84, Ala97, and Arg104 have been mutant as cysteine for mono PEGylation, respectively. According to the relative immunogenicity of Sak or its PEGylation derivatives, the amount of specific anti-Sak IgG antibodies elicited by PEGylation proteins, including C79G, C82L, C84K, C97A, and C104R in BALB/c mice decreased by approximately 15–75% each. PEGylated Sak derivatives showed a decrease of up to 75% in the immune reactivity in PEG-Sak-C104R. Thrombelastography experiments showed that two PEG-conjugated derivatives, PEG-Sak-C97A (Ly30, 68.14 ± 2.51%) and PEG-Sak-C104R (Ly30, 66.49 ± 5.97%), the LY30 of PEG-Sak-C97A, and PEG-Sak-C104R produced values very similar to those of wild-type Sak. The fibrin plate assays showed the bioactivity of PEG-Sak-C104R to exhibit the most activity approximately as much as urokinase (diameter of halo pattern, 18.6 ± 1.06 mm) and tPA (diameter of halo pattern, 17.2 ± 0.49 mm). The Sak PEGylation derivative PEG-Sak-C104R was also selected for further in vivo activity experimentation. The thrombolytic ability of PEG-Sak-C104R is a little lower than wild-type Sak, whereas, this PEGylated protein retained high activity suitable for thrombolytic therapy. Collectively, with the in vivo and in vitro experiments, the present study suggests that site mutant PEGylation, PEG-Sak-C104R, is a suitable type of PEGylation for clinical applications. Further optimization would help maintain the bioactivity and decrease the immunogenicity of staphylokinase.

Farnesoid X receptor (FXR) has become a particularly attractive target for the discovery of drugs for the treatment of liver and metabolic diseases. Obeticholic acid (), a FXR agonist, has advanced into clinical phase III trials in patients with nonalcoholic steatohepatitis (NASH), but adverse effects (e.g., pruritus, LDL increase) were observed. Pruritus might be induced by Takeda G-protein-coupled receptor 5 (TGR5, GPBAR1), and there are chances to develop FXR agonists with higher selectivity over TGR5. In this letter, novel bile acids bearing different modifications on ring A and side chain of are reported and discussed. Our results indicated that the side chain of is amenable to a variety of chemical modifications with good FXR potency . Especially, compound not only showed promising FXR potency and excellent pharmacokinetic properties, but also proved superior pharmacological efficacy in the HFD + CCl model.

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In this study, we investigated the mechanism of hepatitis B virus (HBV)‐enveloped particle release. Specifically, we used preS1 as a bait protein to screen host proteins using mass spectroscopy, with the results of immunofluorescence, western blot, co‐immunoprecipitation, isothermal titration calorimetry, and pull‐down assays identifying glucose‐regulated protein (GRP)78 as a specific target for preS1 binding. We employed transcriptome sequencing, enzyme‐linked immunosorbent assays, and particle gel assays to investigate the mechanism of GRP78‐mediated positive regulation of HBV‐enveloped particle release. Additionally, we performed phage‐display, surface plasmon resonance, and molecular‐docking assays to assess peptides inhibiting enveloped‐particle release. We found that HBV upregulated GRP78 expression in liver cell lines and the serum of patients with chronic hepatitis B. Furthermore, GRP78 promoted the release of HBV‐enveloped particles in vitro and in vivo within an HBV transgenic mouse model. Moreover, we identified interactions of preS1 peptides with GRP78 via hydrogen bonding and hydrophobic interactions, which effectively inhibited its interaction with HBV‐enveloped particles and their subsequent release. These findings provide novel insights regarding HBV virion release, and demonstrated that GRP78 interacted with preS1 to positively regulate the release of HBV‐enveloped particles, suggesting GRP78 as a potential therapeutic target for inhibiting HBV infection.