Search

Coxsackievirus B3 (CVB3) is a member of the enterovirus genus and linked to several diseases, including myocarditis, which can progress to dilated cardiomyopathy. Despite ongoing preclinical efforts, no clinically approved vaccines against CVB3 are currently available, highlighting the urgent need for effective prophylactic solutions. In this study, a nanovaccine platform based on spider minor ampullate silk protein (MiSp) is introduced. This platform utilizes protein nanoparticles engineered from chimeric proteins that incorporate CVB3 antigenic peptides into customized MiSp, subsequently loaded with all‐trans retinoic acid (RA). These functional nanovaccines are capable of eliciting both mucosal and systemic immune responses following subcutaneous administration and demonstrate significant protective effects against CVB3 infection in mice. This study signifies an approach in peptide‐based parenteral vaccine strategies, utilizing engineered MiSp nanoparticles combined with RA. This methodology represents a promising pathway for preventing enterovirus infections by leveraging the unique immunomodulatory properties of spidroins and RA to combat these pathogens effectively. [ABSTRACT FROM AUTHOR]

Spider silk—an environmentally friendly protein‐based material—is widely recognized for its extraordinary mechanical properties. Biomimetic spider silk‐like fibers made from recombinant spider silk proteins (spidroins) currently falls short compared to natural silks in terms of mechanical performance. In this study, it is discovered that spiders use structural conversion of molecular enhancers—conserved globular 127‐residue spacer domains—to make strong silk fibers. This domain lacks poly‐Ala motifs but interestingly contains motifs that are similar to human amyloidogenic motifs, and that it self‐assembles into amyloid‐like fibrils through a non‐nucleation‐dependent pathway, likely to avoid the formation of cytotoxic intermediates. Incorporating this spacer domain into a recombinant chimeric spidroin facilitates self‐assembly into silk‐like fibers, increases fiber molecular homogeneity, and markedly enhances fiber mechanical strength. These findings highlight that spiders employ diverse strategies to produce silk with exceptional mechanical properties. The spacer domain offers a way to enhance the properties of recombinant spider silk‐like fibers and other functional materials. [ABSTRACT FROM AUTHOR]

In the article "Spiders Use Structural Conversion of Globular Amyloidogenic Domains to Make Strong Silk Fibers," researchers discuss how spiders utilize the structural conversion of conserved globular spacer domains to create strong silk fibers. These domains, which contain motifs similar to human amyloidogenic motifs, self-assemble into amyloid-like fibrils through a non-nucleation-dependent pathway. The integration of this spacer into a chimeric spidroin enhances silk-like fiber assembly, improves molecular homogeneity, and significantly strengthens the fibers. The study was conducted by Gefei Chen and a team of researchers. [Extracted from the article]

Abstract: Previously, the C-terminal fragment of a split intein was known to undergo controllable C-cleavage at its C-terminus only when the N-terminal fragment of the intein was added. Here we constructed a similar split intein from the Ssp DnaX intein, but we unexpectedly observed that its C-terminal 136-aa fragment could undergo spontaneous C-cleavage without the N-terminal fragment that was up to 15 aa long and contained the conserved intein motif A. This C-cleavage activity was significantly decreased by a mutation of the conserved Thr residue in the conserved intein motif B. These findings suggest a robust intein structure in the absence of motif A and a larger role of motif B in the third step of the protein splicing mechanism. [Copyright &y& Elsevier]

Background: Oral vaccine is highly desired for infectious disease which is caused by pathogens infection through the mucosal surface. The design of suitable vaccine delivery system is ongoing for the antigen protection from the harsh gastric environment and target to the Peyer's patches to induce sufficient mucosal immune responses. Among various potential delivery systems, bacterial inclusion bodies have been widely used as delivery systems in the field of nanobiomedicine. However, a large number of heterologous complex proteins could be difficult to propagate in E. coli and fusion partners are often used to enhance target protein expression. As a safety concern the fusion protein need to be removed from the target protein to get tag-free protein, especially for the production of protein antigen in vaccinology. Until now, there is no report on how to remove fusion tag from inclusion body particles in vitro and in vivo. Coxsackievirus B3 (CVB3) is a leading causative agent of viral myocarditis and orally protein vaccine is high desired for CVB3-induced myocarditis. In this context, we explored a tag-free VP1 inclusion body nanoparticles production protocol though a truncated Ssp DnaX mini-intein spontaneous C-cleavage in vivo and also exploited the VP1 inclusion bodies as an oral protein nanoparticle vaccine to protect mice against CVB3-induced myocarditis. Results: We successfully produced the tag-free VP1 inclusion body nanoparticle antigen of CVB3 and orally administrated to mice. The results showed that the tag-free VP1 inclusion body nanoparticles as an effective antigen delivery system targeting to the Peyer's patches had the capacity to induce mucosal immunity as well as to efficiently protect mice from CVB3 induce myocarditis without any adjuvant. Then, we proposed the use of VP1 inclusion body nanoparticles as good candidate for oral vaccine to against CVB3-induced myocarditis. Conclusions: Our tag-free inclusion body nanoparticles production procedure is easy and low cost and may have universal applicability to produce a variety of tag-free inclusion body nanoparticles for oral vaccine. [ABSTRACT FROM AUTHOR]

CVB3 is a common human pathogen to be highly lethal to newborns and causes viral myocarditis and pancreatitis in adults. However, there is no vaccine available for clinical use. CVB3 capsid protein VP1 is an immunodominant structural protein, containing several B- and T-cell epitopes. However, immunization of mice with VP1 protein is ineffective. Cyclization of peptide is commonly used to improve their in vivo stability and biological activity. Here, we designed and synthesizd cyclic VP1 protein by using engineered split Rma DnaB intein and the cyclization efficiency was 100% in E. coli. As a result, the cyclic VP1 was significantly more stable against irreversible aggregation upon heating and against carboxypeptidase in vitro and the degradation rate was more slowly in vivo. Compared with linear VP1, immunization mice with circular VP1 significantly increased CVB3-specific serum IgG level and augmented CVB3-specific cellular immune responses, consequently afforded better protection against CVB3-induced viral myocarditis. The cyclic VP1 may be a novel candidate protein vaccine for preventing CVB3 infection and similar approaches could be employed to a variety of protein vaccines to enhance their protection effect. [ABSTRACT FROM AUTHOR]

Background: Spider silk is a proteinaceous fiber with remarkable mechanical properties spun from spider silk proteins (spidroins). Engineering spidroins have been successfully produced in a variety of heterologous hosts and the most widely used expression system is Escherichia coli (E. coli). So far, recombinantly expressed spidroins often form insoluble inclusion bodies (IBs), which will often be dissolved under extremely harsh conditions in a traditional manner, e.g. either 8 mol/L urea or 6 mol/L guanidine hydrochloride, highly risking to poor recovery of bioactive proteins as well as unexpected precipitations during dialysis process. Results: Here, we present a mild solubilization strategy—one-step heating method to solubilize spidroins from IBs, with combining spidroins' high thermal stability with low concentration of urea. A 430-aa recombinant protein (designated as NM) derived from the minor ampullate spidroin of Araneus ventricosus was expressed in E. coli, and the recombinant proteins were mainly present in insoluble fraction as IBs. The isolated IBs were solubilized parallelly by both traditional urea-denatured method and one-step heating method, respectively. The solubilization efficiency of NM IBs in Tris-HCl pH 8.0 containing 4 mol/L urea by one-step heating method was already comparable to that of 7 mol/L urea with using traditional urea-denatured method. The effects of buffer, pH and temperature conditions on NM IBs solubilization of one-step heating method were evaluated, respectively, based on which the recommended conditions are: heating temperature 70–90 °C for 20 min, pH 7.0–10, urea concentration 2–4 mol/L in normal biological buffers. The recombinant NM generated via the one-step heating method held the potential functions with self-assembling into sphere nanoparticles with smooth morphology. Conclusions: The one-step heating method introduced here efficiently solubilizes IBs under relatively mild conditions compared to the traditional ones, which might be important for the downstream applications; however, this protocol should be pursued carefully in terms of urea-induced modification sensitive applications. Further, this method can be applied under broad buffer, pH and temperature conditions, conferring the potential to apply to other thermal stable proteins. [ABSTRACT FROM AUTHOR]