Cytokine conjugates to elastin-like polypeptides

Thermo-pH-Sensitive Polypeptides Boost Protein Drug's Tumor Permeation and Pharmacology

Proteins are typically subject to poor stability, short half-life, and poor cell and tissue permeability, which restrict their wide applications as drugs for disease treatment. Current protein modification techniques mostly focus on improving the stability and half-life of proteins, but hardly solve their poor cell and tissue permeability. To address this issue, the study innovatively designs thermo-pH-sensitive elastin-like polypeptides to modify proteins, named ELP(HX)n in which histidine (H) and any amino acid except proline (X) are guest amino acids in the polypeptides and n is the total number of the guest amino acids. H in ELP(HX)n can be protonated under acidic conditions. To prove the concept, an important protein drug of L-asparaginase (ASP) is genetically fused to ELP(HV)60 to generate ASP-ELP(HV)60. Compared with ASP and PEGylated ASP, ASP-ELP(HV)60 exhibits not only elevated stability and extended half-life but also enhanced tumor cell and tissue penetration, resulting in improved antitumor efficacy. These findings demonstrate that ELP(HX)n fusion is a novel and general protein modification method to overcome the intrinsic limitations of proteins as therapeutics, rendering it feasible to design intelligent protein therapeutics, especially for efficient tumor therapy.

Leech bionic Hirudin fusion protein prodrug loaded microneedles for long-term inhibition of thrombosis

The clinical use of anticoagulant drugs for thrombosis is limited by short half-life and bleeding risk, requiring frequent administration and close monitoring. Here, inspired by leech mouthparts, we present a hirudin-based fusion protein prodrug incorporated with microneedles (MNs) for long-term antithrombotic therapy to achieve a simplified dosing regimen, continuous protection, and on-demand antithrombotic bioactivity recovery. Genetic-engineered anticoagulant prodrugs are precisely customized by fusing hirudin to elastin-like polypeptides with adjustable assembly characteristics. The introduction of elastin-like polypeptides can shield the biological activity of hirudin, drive the self-assembly of fusion proteins, and prolong their half-life in vivo. The fusion protein prodrugs circulate in the blood as sentinels and accumulate in the thrombus site with the assistance of the clot-targeted motif. Under the catalysis of FXa during thrombosis, the fusion protein prodrugs adaptively restore anticoagulant activity to inhibit thrombus formation. Notably, the assembled prodrugs were integrated into an MN matrix made of silk fibroin and chitosan through photopolymerization for long-term controlled release and facile self-administration. It was proved that the bionic MNs conveniently provide long protection against thrombosis without increasing bleeding events. These excellent performances indicate that the bionic MN patch has broad application prospects in thrombosis and related diseases.

Self-assembled nanoparticles of hybrid elastin-like and Oncostatin M polymers for improved wound healing

Oncostatin M (OSM) is a pleiotropic cytokine that can significantly enhance wound healing. Here, we report on the use of nanoparticles (NPs) formulated from a genetically engineered A200_hOSM protein polymer, which combines an elastin-like recombinamer (A200) with human OSM (hOSM) in the same molecule, aiming at enhancing wound healing processes. A200_hOSM NPs were obtained by self-assembly and evaluated for their bioactivity in human keratinocytes and fibroblasts. The NPs demonstrated superior efficacy in promoting cell proliferation in a dose-dependent manner, exhibiting nearly threefold greater proliferation at 48 and 72 h, compared to cells treated with commercial hOSM. Moreover, the NPs stimulated cell migration and collagen production through activation of JAK/STAT3 signaling. They also promoted the production of IL-6 and IL-8, pro-inflammatory cytokines with a critical role for wound healing. Promotion of keratinocyte proliferation and differentiation were further validated in non-commercial 3D skin equivalents. The A200_hOSM NPs revealed potential in accelerating wound healing, evidenced by reduced wound size and a thicker epidermal layer. This system represents a significant advancement in the field of bioinspired biomaterials by improving cytokine bioavailability, allowing for localized therapy and offering a cost-effective strategy for employing hOSM in wound healing management.

An ultra-long-acting L-asparaginase synergizes with an immune checkpoint inhibitor in starvation-immunotherapy of metastatic solid tumors

Metastasis stands as the primary contributor to mortality associated with tumors. Chemotherapy and immunotherapy are frequently utilized in the management of metastatic solid tumors. Nevertheless, these therapeutic modalities are linked to serious adverse effects and limited effectiveness in preventing metastasis. Here, we report a novel therapeutic strategy named starvation-immunotherapy, wherein an immune checkpoint inhibitor is combined with an ultra-long-acting L-asparaginase that is a fusion protein comprising L-asparaginase (ASNase) and an elastin-like polypeptide (ELP), termed ASNase-ELP. ASNase-ELP's thermosensitivity enables it to generate an in-situ depot following an intratumoral injection, yielding increased dose tolerance, improved pharmacokinetics, sustained release, optimized biodistribution, and augmented tumor retention compared to free ASNase. As a result, in murine models of oral cancer, melanoma, and cervical cancer, the antitumor efficacy of ASNase-ELP by selectively and sustainably depleting L-asparagine essential for tumor cell survival was substantially superior to that of ASNase or Cisplatin, a first-line anti-solid tumor medicine, without any observable adverse effects. Furthermore, the combination of ASNase-ELP and an immune checkpoint inhibitor was more effective than either therapy alone in impeding melanoma metastasis. Overall, the synergistic strategy of starvation-immunotherapy holds excellent promise in reshaping the therapeutic landscape of refractory metastatic tumors and offering a new alternative for next-generation oncology treatments.

Upregulation of NK cell activity, cytokine expression, and NF-κB pathway by ginsenoside concentrates from Panax ginseng berries in healthy mice and macrophage cell lines

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng (P. ginseng) C.A. Meyer. Has been studied for decades for its various biological activities, especially in terms of immune-regulatory properties. Traditionally, it has been known that root, leaves, and fruits of P. ginseng were eaten for improving body's Qi and homeostasis. Also, these were used to protect body from various types of infectious diseases. However, molecular mechanisms of immunomodulatory activities of ginseng berries have not been systemically studied as often as other parts of the plant.

AIM OF THE STUDY

The aim of this research is to discover the regulatory effects of P. ginseng berries, more importantly, their ginsenosides, on innate immune responses and to elucidate the molecular mechanism.

MATERIALS AND METHODS

Ginseng berry concentrate (GBC) was orally injected into BALB/c mice for 30 days, and spleens were extracted for evaluation of immune-regulatory effects. Murine macrophage RAW264.7 cells were used for detailed molecular mechanism studies. Splenic natural killer (NK) cells were isolated using the magnetic-activated cell sorting (MACS) system, and the cytotoxic activity of isolated NK cells was measured using a lactate dehydrogenase (LDH) release assay. The splenic immune cell population was determined by flow-cytometry. NF-κB promoter activity was assessed by in vitro luciferase assay. Expression of inflammatory proteins and cytokines of the spleen and RAW264.7 cells were evaluated using western blotting and real-time PCR, respectively.

RESULTS

The GBC enhanced cytotoxic activity of NK cells and the immune-regulation-related splenic cell population. Moreover, GBC promoted NF-κB promoter activity and stimulated the NF-κB signaling cascade. In spleen and RAW264.7 cells, expression of pro-inflammatory cytokines was increased upon GBC application, while expression of anti-inflammatory cytokines decreased.

CONCLUSIONS

These results suggest that P. ginseng berry can stimulate innate immune responses and help maintain a balanced immune condition, mostly due to the action of its key ginsenoside Re, along with other protopanaxadiol- and protopanaxatriol-type ginsenosides. Such finding will provide a new insight into the field of well-being diet research as well as non-chemical immune modulator, by providing nature-derived and plant-based bioactive materials.

Multifunctional polypeptide-based hydrogel bio-adhesives with pro-healing activities and their working principles

Wound healing is a complex physiological process involving hemostasis, inflammation, proliferation, and tissue remodeling. Therefore, there is an urgent need for suitable wound dressings for effective and systematical wound management. Polypeptide-based hydrogel bio-adhesives offer unique advantages and are ideal candidates. However, comprehensive reviews on polypeptide-based hydrogel bio-adhesives for wound healing are still lacking. In this review, the physiological mechanisms and evaluation parameters of wound healing were first described in detail. Then, the working principles of hydrogel bio-adhesives were summarized. Recent advances made in multifunctional polypeptide-based hydrogel bio-adhesives involving gelatin, silk fibroin, fibrin, keratin, poly-γ-glutamic acid, ɛ-poly-lysine, serum albumin, and elastin with pro-healing activities in wound healing and tissue repair were reviewed. Finally, the current status, challenges, developments, and future trends of polypeptide-based hydrogel bio-adhesives were discussed, hoping that further developments would be stimulated to meet the growing needs of their clinical applications.

Structural and physical basis for the elasticity of elastin

Elastin function is to endow vertebrate tissues with elasticity so that they can adapt to local mechanical constraints. The hydrophobicity and insolubility of the mature elastin polymer have hampered studies of its molecular organisation and structure-elasticity relationships. Nevertheless, a growing number of studies from a broad range of disciplines have provided invaluable insights, and several structural models of elastin have been proposed. However, many questions remain regarding how the primary sequence of elastin (and the soluble precursor tropoelastin) governs the molecular structure, its organisation into a polymeric network, and the mechanical properties of the resulting material. The elasticity of elastin is known to be largely entropic in origin, a property that is understood to arise from both its disordered molecular structure and its hydrophobic character. Despite a high degree of hydrophobicity, elastin does not form compact, water-excluding domains and remains highly disordered. However, elastin contains both stable and labile secondary structure elements. Current models of elastin structure and function are drawn from data collected on tropoelastin and on elastin-like peptides (ELPs) but at the tissue level, elasticity is only achieved after polymerisation of the mature elastin. In tissues, the reticulation of tropoelastin chains in water defines the polymer elastin that bears elasticity. Similarly, ELPs require polymerisation to become elastic. There is considerable interest in elastin especially in the biomaterials and cosmetic fields where ELPs are widely used. This review aims to provide an up-to-date survey of/perspective on current knowledge about the interplay between elastin structure, solvation, and entropic elasticity.

Essential factors, advanced strategies, challenges, and approaches involved for efficient expression of recombinant proteins in Escherichia coli

Producing recombinant proteins is a major accomplishment of biotechnology in the past century. Heterologous hosts, either eukaryotic or prokaryotic, are used for the production of these proteins. The utilization of microbial host systems continues to dominate as the most efficient and affordable method for biotherapeutics and food industry productions. Hence, it is crucial to analyze the limitations and advantages of microbial hosts to enhance the efficient production of recombinant proteins on a large scale. E. coli is widely used as a host for the production of recombinant proteins. Researchers have identified certain obstacles with this host, and given the growing demand for recombinant protein production, there is an immediate requirement to enhance this host. The following review discusses the elements contributing to the manifestation of recombinant protein. Subsequently, it sheds light on innovative approaches aimed at improving the expression of recombinant protein. Lastly, it delves into the obstacles and optimization methods associated with translation, mentioning both cis-optimization and trans-optimization, producing soluble recombinant protein, and engineering the metal ion transportation. In this context, a comprehensive description of the distinct features will be provided, and this knowledge could potentially enhance the expression of recombinant proteins in E. coli.

A Superlong-Acting Growth Hormone-Polypeptide Fusion for Growth Hormone Deficiency Treatment

Recombinant human growth hormone (rhGH) is clinically used to treat growth hormone deficiency (GHD). However, daily administration of rhGH is required due to its poor stability and short blood circulation, which causes pains and burdens as well as inconvenience to patients. In this study, a method for genetically fusing rhGH to a thermosensitive polymer of elastin-like polypeptide (ELP) is reported, using which the rhGH-ELP thermosensitive fusion protein can be purified by the thermosensitivity of ELP instead of chromatography. The ELP fusion not only drastically improves the stability of rhGH, but also enables the in situ formation of a sustained-release depot of rhGH-ELP upon subcutaneous (SC) injection, which exhibits gentle release with a platform-to-trough fluctuation in blood and a very long circulatory half-life of 594.6 h. In contrast, rhGH exhibits a peak-to-trough fluctuation in blood with a very short circulatory half-life of 0.7 h. As a result, a single subcutaneous injection of rhGH-ELP can consecutively promote the linear growth of rats and the development of major tissues and organs over 3 weeks without obvious side effects, whereas rhGH is required to be injected daily to achieve similar therapeutic results.

Thermoresponsive Polypeptide Fused L-Asparaginase with Mitigated Immunogenicity and Enhanced Efficacy in Treating Hematologic Malignancies

L-Asparaginase (ASP) is well-known for its excellent efficacy in treating hematological malignancies. Unfortunately, the intrinsic shortcomings of ASP, namely high immunogenicity, severe toxicity, short half-life, and poor stability, restrict its clinical usage. Poly(ethylene glycol) conjugation (PEGylation) of ASP is an effective strategy to address these issues, but it is not ideal in clinical applications due to complex chemical synthesis procedures, reduced ASP activity after conjugation, and pre-existing anti-PEG antibodies in humans. Herein, the authors genetically engineered an elastin-like polypeptide (ELP)-fused ASP (ASP-ELP), a core-shell structured tetramer predicted by AlphaFold2, to overcome the limitations of ASP and PEG-ASP. Notably, the unique thermosensitivity of ASP-ELP enables the in situ formation of a sustained-release depot post-injection with zero-order release kinetics over a long time. The in vitro and in vivo studies reveal that ASP-ELP possesses increased activity retention, improved stability, extended half-life, mitigated immunogenicity, reduced toxicity, and enhanced efficacy compared to ASP and PEG-ASP. Indeed, ASP-ELP treatment in leukemia or lymphoma mouse models of cell line-derived xenograft (CDX) shows potent anti-cancer effects with significantly prolonged survival. The findings also indicate that artificial intelligence (AI)-assisted genetic engineering is instructive in designing protein-polypeptide conjugates and may pave the way to develop next-generation biologics to enhance cancer treatment.

A histidine-rich fusion tag enables real-time monitoring of recombinant protein expression by Pauly reaction-based colorimetric assay

Commercially available recombinant expression systems always use fusion tags to facilitate target protein purification and SDS-PAGE analysis followed by Coomassie Brilliant Blue (CBB) staining is the classical method to validate the expression level of target protein, which is time-consuming, although not very laborious. Previously, we found that a histidine-rich elastin-like polypeptide (HRELP) tag could make its fusion proteins being quickly and specifically stained with Pauly's reagent. In this study, we designed a Pauly reaction-based colorimetric assay to real-time monitoring of the expression level of recombinant protein tagged HRELP and found that the absorption value of post-induction E. coli cells stained with Pauly's reagent correlated well with both the band intensity of the target protein from Pauly's reagent-stained and CBB-stained gels. Moreover, we found the colorimetric assay could also be helpful to roughly estimate the expression efficiency by using a poly-histidine-tagged protein, which has only 1.17% histidine residue. In our opinion, Pauly reaction-based colorimetric assay could significantly shorten the time to validate the over-expression of recombinant protein tagged with either HRELP or poly-histidine. And HRELP seemed to be an ideal fusion tag for it can not only facilitate protein purification but also simplify protein detection.

Factors involved in heterologous expression of proteins in E. coli host

The production of recombinant proteins is one of the most significant achievements of biotechnology in the last century. These proteins are produced in the eukaryotic or prokaryotic heterologous hosts. By increasing the omics data especially related to different heterologous hosts as well as the presence of new amenable genetic engineering tools, we can artificially engineer heterologous hosts to produce recombinant proteins in sufficient quantities. Numerous recombinant proteins have been produced and applied in various industries, and the global recombinant proteins market size is expected to be cast to reach USD 2.4 billion by 2027. Therefore, identifying the weakness and strengths of heterologous hosts is critical to optimize the large-scale biosynthesis of recombinant proteins. E. coli is one of the popular hosts to produce recombinant proteins. Scientists reported some bottlenecks in this host, and due to the increasing demand for the production of recombinant proteins, there is an urgent need to improve this host. In this review, we first provide general information about the E. coli host and compare it with other hosts. In the next step, we describe the factors involved in the expression of the recombinant proteins in E. coli. Successful expression of recombinant proteins in E. coli requires a complete elucidation of these factors. Here, the characteristics of each factor will be fully described, and this information can help to improve the heterologous expression of recombinant proteins in E. coli.