Balancing the Expression and Production of a Heterodimeric Protein: Recombinant Agkisacutacin as a Novel Antithrombotic Drug Candidate

From lignocellulosic biomass to single cell oil for sustainable biomanufacturing: Current advances and prospects

As global temperatures rise and arid climates intensify, the reserves of Earth's resources and the future development of humankind are under unprecedented pressure. Traditional methods of food production are increasingly inadequate in meeting the demands of human life while remaining environmentally sustainable and resource-efficient. Consequently, the sustainable supply of lipids is expected to become a pivotal area for future food development. Lignocellulose biomass (LB), as the most abundant and cost-effective renewable resource, has garnered significant attention from researchers worldwide. Thus, bioprocessing based on LB is appearing as a sustainable model for mitigating the depletion of energy reserves and reducing carbon footprints. Currently, the transformation of LB primarily focuses on producing biofuels, such as bioethanol, biobutanol, and biodiesel, to address the energy crisis. However, there are limited reports on the production of single cell oil (SCO) from LB. This review, therefore, provides a comprehensive summary of the research progress in lignocellulosic pretreatment. Subsequently, it describes how the capability for lignocellulosic use can be conferred to cells through genetic engineering. Additionally, the current status of saccharification and fermentation of LB is outlined. The article also highlights the advances in synthetic biology aimed at driving the development of oil-producing microorganism (OPM), including genetic transformation, chassis modification, and metabolic pathway optimization. Finally, the limitations currently faced in SCO production from straw are discussed, and future directions for achieving high SCO yields from various perspectives are proposed. This review aims to provide a valuable reference for the industrial application of green SCO production.

Urokinase-loaded cyclic RGD-decorated liposome targeted therapy for in-situ thrombus of pulmonary arteriole of pulmonary hypertension

Backgroud: In-situ thrombosis is a significant pathophysiological basis for the development of pulmonary hypertension (PH). However, thrombolytic therapy for in-situ thrombus in PH was often hampered by the apparent side effects and the low bioavailability of common thrombolytic medications. Nanoscale cyclic RGD (cRGD)-decorated liposomes have received much attention thanks to their thrombus-targeting and biodegradability properties. As a result, we synthesized urokinase-loaded cRGD-decorated liposome (UK-cRGD-Liposome) for therapy of in-situ thrombosis as an exploration of pulmonary hypertensive novel therapeutic approaches. Purpose: To evaluate the utilize of UK-cRGD-Liposome for targeted thrombolysis of in-situ thrombus in PH and to explore the potential mechanisms of in-situ thrombus involved in the development of PH. Methods: UK-cRGD-Liposome nanoscale drug delivery system was prepared using combined methods of thin-film hydration and sonication. Induced PH via subcutaneous injection of monocrotaline (MCT). Fibrin staining (modified MSB method) was applied to detect the number of vessels within-situ thrombi in PH. Echocardiography, hematoxylin-eosin (H & E) staining, and Masson's trichrome staining were used to analyze right ventricular (RV) function, pulmonary vascular remodeling, as well as RV remodeling. Results: The number of vessels with in-situ thrombi revealed that UK-cRGD-Liposome could actively target urokinase to in-situ thrombi and release its payload in a controlled manner in the in vivo environment, thereby enhancing the thrombolytic effect of urokinase. Pulmonary artery hemodynamics and echocardiography indicated a dramatical decrease in pulmonary artery pressure and a significant improvement in RV function post targeted thrombolytic therapy. Moreover, pulmonary vascular remodeling and RV remodeling were significantly restricted post targeted thrombolytic therapy. Conclusion: UK-cRGD-Liposome can restrict the progression of PH and improve RV function by targeting the dissolution of pulmonary hypertensive in-situ thrombi, which may provide promising therapeutic approaches for PH.

The chemistry of snake venom and its medicinal potential

The fascination and fear of snakes dates back to time immemorial, with the first scientific treatise on snakebite envenoming, the Brooklyn Medical Papyrus, dating from ancient Egypt. Owing to their lethality, snakes have often been associated with images of perfidy, treachery and death. However, snakes did not always have such negative connotations. The curative capacity of venom has been known since antiquity, also making the snake a symbol of pharmacy and medicine. Today, there is renewed interest in pursuing snake-venom-based therapies. This Review focuses on the chemistry of snake venom and the potential for venom to be exploited for medicinal purposes in the development of drugs. The mixture of toxins that constitute snake venom is examined, focusing on the molecular structure, chemical reactivity and target recognition of the most bioactive toxins, from which bioactive drugs might be developed. The design and working mechanisms of snake-venom-derived drugs are illustrated, and the strategies by which toxins are transformed into therapeutics are analysed. Finally, the challenges in realizing the immense curative potential of snake venom are discussed, and chemical strategies by which a plethora of new drugs could be derived from snake venom are proposed.

Effect of two preservation methods on the viability and enzyme production of a recombinant Komagataella phaffii (Pichia pastoris) strain

The methylotrophic yeast Komagataella phaffii, previously known as Pichia pastoris, has been reported as a host for producing human recombinant lysosomal enzymes intended for enzyme replacement therapy. K. phaffii has advantages such as easy genetic handling, rapid growth, cost-effective mediums, and the ability to develop mammalian-like post-translational modifications. To maintain cell viability and enzyme activity over time, it is important to consider the bioprocess optimization and the proper selection and preservation of clones. In this study, we evaluated the effect of glycerol and skim milk in cryopreservation at -80 °C, as well as the use of skim milk or its combination with NaCl, disaccharides or sorbitol in freeze-drying on the cell viability and activity of a recombinant lysosomal enzyme (i.e., human β-hexosaminidase-A) produced in K. phaffii GS115 strain. The results showed that cryopreservation with glycerol and skim milk, as well as freeze-drying using disaccharides and sorbitol with skim milk, maintained the viability above 80%. Although variations in enzyme activity among treatments were found, the use of disaccharides had a positive effect on the enzymatic activity levels. This is the first report of the evaluation of two suitable methods to preserve a recombinant K. phaffii strain, preventing the loss of viability and maintaining the activity of the recombinant protein.

In vitro assessment and phase I randomized clinical trial of anfibatide a snake venom derived anti-thrombotic agent targeting human platelet GPIbα

The interaction of platelet GPIbα with von Willebrand factor (VWF) is essential to initiate platelet adhesion and thrombosis, particularly under high shear stress conditions. However, no drug targeting GPIbα has been developed for clinical practice. Here we characterized anfibatide, a GPIbα antagonist purified from snake (Deinagkistrodon acutus) venom, and evaluated its interaction with GPIbα by surface plasmon resonance and in silico modeling. We demonstrated that anfibatide interferds with both VWF and thrombin binding, inhibited ristocetin/botrocetin- and low-dose thrombin-induced human platelet aggregation, and decreased thrombus volume and stability in blood flowing over collagen. In a single-center, randomized, and open-label phase I clinical trial, anfibatide was administered intravenously to 94 healthy volunteers either as a single dose bolus, or a bolus followed by a constant rate infusion of anfibatide for 24 h. Anfibatide inhibited VWF-mediated platelet aggregation without significantly altering bleeding time or coagulation. The inhibitory effects disappeared within 8 h after drug withdrawal. No thrombocytopenia or anti-anfibatide antibodies were detected, and no serious adverse events or allergic reactions were observed during the studies. Therefore, anfibatide was well-tolerated among healthy subjects. Interestingly, anfibatide exhibited pharmacologic effects in vivo at concentrations thousand-fold lower than in vitro, a phenomenon which deserves further investigation.Trial registration: Clinicaltrials.gov NCT01588132.

Improved the expression level of active transglutaminase by directional increasing copy of mtg gene in Pichia pastoris

Background

The microbial transglutaminase (MTG) is inactive when only the mature sequence is expressed in Pichia pastoris. Although co-expression of MTG and its N-terminal pro-peptide can obtain the active MTG, the enzyme activity was still low. One of the basic steps for strain improvement is to ensure a sufficient level of transcription of the heterologous gene, based on promoter strength and gene copy number. To date, high-copy-number recombinants of P. pastoris are achievable only by cloning of gene concatemers, so methods for rapid and reliable multicopy strains are therefore desirable.

Results

The coexpression strains harboring different copies mtg were obtained successfully by stepwise increasing Zeocin concentration based on the rDNA sequence of P. pastoris. The genome of coexpression strains with the highest enzyme activity was analyzed by real-time fluorescence quantitative PCR, and three copies of mtg gene (mtg-3c) was calculated according to the standard curve of gap and mtg genes (gap is regarded as the single-copy reference gene). The maximum enzyme activity of mtg-3c was up to 1.41 U/mL after being inducted for 72 h in 1 L flask under optimal culture conditions, and two protein bands were observed at the expected molecular weights (40 kDa and 5 kDa) by Western blot. Furthermore, among the strains detected, compared with mtg-2c, mtg-6c or mtg-8c, mtg-3c is the highest expression level and enzyme activity, implying that mtg-3c is the most suitable for co-expression pro-peptide and MTG.

Conclusions

This study provides an effective strategy for improving the expression level of active MTG by directional increasing of mtg copies in P. pastoris.

Electronic supplementary material

The online version of this article (10.1186/s12896-019-0542-6) contains supplementary material, which is available to authorized users.

Snake venom components in medicine: From the symbolic rod of Asclepius to tangible medical research and application

Both mythologically and logically, snakes have always fascinated man. Snakes have attracted both awe and fear not only because of the elegant movement of their limbless bodies, but also because of the potency of their deadly venoms. Practically, in 2017, the world health organization (WHO) listed snake envenomation as a high priority neglected disease, as snakes inflict up to 2.7 million poisonous bites, around 100.000 casualties, and about three times as many invalidities on man. The venoms of poisonous snakes are a cocktail of potent compounds which specifically and avidly target numerous essential molecules with high efficacy. The individual effects of all venom toxins integrate into lethal dysfunctions of almost any organ system. It is this efficacy and specificity of each venom component, which after analysis of its structure and activity may serve as a potential lead structure for chemical imitation. Such toxin mimetics may help in influencing a specific body function pharmaceutically for the sake of man's health. In this review article, we will give some examples of snake venom components which have spurred the development of novel pharmaceutical compounds. Moreover, we will provide examples where such snake toxin-derived mimetics are in clinical use, trials, or consideration for further pharmaceutical exploitation, especially in the fields of hemostasis, thrombosis, coagulation, and metastasis. Thus, it becomes clear why a snake captured its symbolic place at the Asclepius rod with good reason still nowadays.

Applications of Yeast Synthetic Biology Geared towards the Production of Biopharmaceuticals

Engineered yeast are an important production platform for the biosynthesis of high-value compounds with medical applications. Recent years have witnessed several new developments in this area, largely spurred by advances in the field of synthetic biology and the elucidation of natural metabolic pathways. This minireview presents an overview of synthetic biology applications for the heterologous biosynthesis of biopharmaceuticals in yeast and demonstrates the power and potential of yeast cell factories by highlighting several recent examples. In addition, an outline of emerging trends in this rapidly-developing area is discussed, hinting upon the potential state-of-the-art in the years ahead.

Elimination of N-glycosylation by site mutation further prolongs the half-life of IFN-α/Fc fusion proteins expressed in Pichia pastoris

Background

Interferon (IFN)-α has been commonly used as an antiviral drug worldwide; however, its short half-life in circulation due to its low molecular weight and sensitivity to proteases impacts its efficacy and patient compliance.

Results

In this study, we present an IgG1 Fc fusion strategy to improve the circulation half-life of IFN-α. Three different forms of IgG1 Fc fragments, including the wild type, aglycosylated homodimer and aglycosylated single chain, were each fused with IFN-α and designated as IFN-α/Fc-WT, IFN-α/Fc-MD, and IFN-α/Fc-SC, respectively. The recombinant proteins were expressed in Pichia pastoris and tested using antiviral and pharmacokinetic assays in comparison with the commercial pegylated-IFN-α (PEG-IFN-α). The in vitro study demonstrated that IFN-α/Fc-SC has the highest antiviral activity, while IFN-α/Fc-WT and IFN-α/Fc-MD exhibited antiviral activities comparable to that of PEG-IFN-α. The in vivo pharmacokinetic assay showed that both IFN-α/Fc-WT and IFN-α/Fc-MD have a longer half-life than PEG-IFN-α in SD rats, but IFN-α/Fc-SC has the shortest half-life among them. Importantly, the circulating half-life of 68.3 h for IFN-α/Fc-MD was significantly longer than those of 38.2 h for IFN-α/Fc-WT and 22.2 h for PEG-IFN-α.

Conclusions

The results demonstrate that the elimination of N-glycosylation by mutation of putative N-glycosylation site further prolongs the half-life of the IFN-α/Fc fusion protein and could present an alternative strategy for extending the half-life of low-molecular-weight proteins expressed by P. pastoris for in vivo studies as well as for future clinical applications.

Electronic supplementary material

The online version of this article (doi:10.1186/s12934-016-0601-9) contains supplementary material, which is available to authorized users.