Investigation on Secondary Structure Alterations of Protein Drugs as an Indicator of Their Biological Activity Upon Thermal Exposure

A new method and mechanism for the rapid detoxification of the herb Pinelliae Rhizoma from the Araceae family, based on the dual destruction of raphides and lectin proteins

Pinelliae Rhizoma (PR), a traditional herbal medicine and dietary supplement, is valued for its cough relief and anti-inflammatory effects. However, it can cause significant throat irritation. And unfortunately, current processing techniques can lead to a considerable loss of active constituents in PR. This study employed microwave irradiation to process PR and elucidated the mechanisms underlying its attenuation of PR's irritation. The results demonstrated that microwave irradiation significantly enhanced the processing efficiency, reducing the traditional processing cycle from 5 to 15 days to just 10 min, while preserving active ingredients and mitigating irritation. Subsequent analysis of the irritant components found that microwave treatment significantly reduced the raphides content, altering their morphology. Concurrently, the secondary structure of lectin proteins underwent significant changes, including an increase in β-sheets, a decrease in β-turns and random coils content, and the formation of insoluble aggregates. In conclusion, microwave irradiation is an effective method for reducing the irritation of PR, with the mechanism attributed to the physical destruction of raphides and alterations in the hydrophobicity of lectin proteins. This study provides a novel approach and method for the processing and development of Araceae herbs, as well as food products such as yam, konjac, and pineapple.

Novel HSA-PMEMA Nanomicelles Prepared via Site-Specific In Situ Polymerization-Induced Self-Assembly for Improved Intracellular Delivery of Paclitaxel

Background/Objectives: Paclitaxel (PTX) is a potent anticancer drug that is poorly soluble in water. To enhance its delivery efficiency in aqueous environments, amphiphilic polymer micelles are often used as nanocarriers for PTX in clinical settings. However, the hydrophilic polymer segments on the surface of these micelles may possess potential immunogenicity, posing risks in clinical applications. To address this issue, nanomicelles based on human serum albumin (HSA)-hydrophobic polymer conjugates constructed via site-specific in situ polymerization-induced self-assembly (SI-PISA) are considered a promising alternative. The HSA shell not only ensures good biocompatibility but also enhances cellular uptake because of endogenous albumin trafficking pathways. Moreover, compared to traditional methods of creating protein-hydrophobic polymer conjugates, SI-PISA demonstrates higher reaction efficiency and better preservation of protein functionality. Methods: We synthesized HSA-PMEMA nanomicelles via SI-PISA using HSA and methoxyethyl methacrylate (MEMA)-a novel hydrophobic monomer with a well-defined and stable chemical structure. The protein activity and the PTX intracellular delivery efficiency of HSA-PMEMA nanomicelles were evaluated. Results: The CD spectra of HSA and HSA-PMEMA exhibited similar shapes, and the relative esterase-like activity of HSA-PMEMA was 94% that of unmodified HSA. Flow cytometry results showed that Cy7 fluorescence intensity in cells treated with HSA-PMEMA-Cy7 was approximately 1.35 times that in cells treated with HSA-Cy7; meanwhile, HPLC results indicated that, under the same conditions, the PTX loading per unit protein mass on HSA-PMEMA was approximately 1.43 times that of HSA. These collectively contributed to a 1.78-fold overall PTX intracellular delivery efficiency of HSA-PMEMA compared to that of HSA. Conclusions: In comparison with HSA, HSA-PMEMA nanomicelles exhibit improved cellular uptake and higher loading efficiency for PTX, effectively promoting the intracellular delivery of PTX. Tremendous potential lies in these micelles for developing safer and more efficient next-generation PTX formulations for tumor treatment.

Effect of processing and formulation factors on Catalase activity in tablets

The manufacturing of tablets containing biologics exposes the biologics to thermal and shear stresses, which are likely to induce structural changes (e.g., aggregation and denaturation), leading to the loss of their activity. Saccharides often act as stabilizers of proteins in formulations, yet their stabilizing ability throughout solid oral dosage processing, such as tableting, has been barely studied. This work aimed to investigate the effects of formulation and process (tableting and spray-drying) variables on catalase tablets containing dextran, mannitol, and trehalose as potential stabilizers. Non-spray-dried and spray-dried formulations were prepared and tableted (100, 200, and 400 MPa). The enzymatic activity, number of aggregates, reflecting protein aggregation and structure modifications were studied. A principal component analysis was performed to reveal underlying correlations. It was found that tableting and spray-drying had a notable negative effect on the activity and number of aggregates formed in catalase formulations. Overall, dextran and mannitol failed to preserve the catalase activity in any unit operation studied. On the other hand, trehalose was found to preserve the activity during spray-drying but not necessarily during tableting. The study demonstrated that formulation and process variables must be considered and optimized together to preserve the characteristics of catalase throughout processing.

Radiolysis of myoglobin concentrated gels by protons: specific changes in secondary structure and production of carbon monoxide

While particle therapy has been used for decades for cancer treatment, there is still a lack of information on the molecular mechanisms of biomolecules radiolysis by accelerated ions. Here, we examine the effects of accelerated protons on highly concentrated native myoglobin, by means of Fourier transform infrared and UV-Visible spectroscopies. Upon irradiation, the secondary structure of the protein is drastically modified, from mostly alpha helices conformation to mostly beta elements at highest fluence. These changes are accompanied by significant production of carbon monoxide, which was shown to come from heme degradation under irradiation. The radiolytic yields of formation of denatured protein, carbon monoxide, and of heme degradation were determined, and found very close to each other: G+denatured Mb ≈ G+CO ≈ G-heme = 1.6 × 10-8 ± 0.1 × 10-8 mol/J = 0.16 ± 0.01 species/100 eV. The denaturation of the protein to a beta structure and the production of carbon monoxide under ion irradiation are phenomena that may play an important role in the biological effects of ionizing radiation.

A Novel 3D Printing Particulate Manufacturing Technology for Encapsulation of Protein Therapeutics: Sprayed Multi Adsorbed-Droplet Reposing Technology (SMART)

Recently, various innovative technologies have been developed for the enhanced delivery of biologics as attractive formulation targets including polymeric micro and nanoparticles. Combined with personalized medicine, this area can offer a great opportunity for the improvement of therapeutics efficiency and the treatment outcome. Herein, a novel manufacturing method has been introduced to produce protein-loaded chitosan particles with controlled size. This method is based on an additive manufacturing technology that allows for the designing and production of personalized particulate based therapeutic formulations with a precise control over the shape, size, and potentially the geometry. Sprayed multi adsorbed-droplet reposing technology (SMART) consists of the high-pressure extrusion of an ink with a well determined composition using a pneumatic 3D bioprinting approach and flash freezing the extrudate at the printing bed, optionally followed by freeze drying. In the present study, we attempted to manufacture trypsin-loaded chitosan particles using SMART. The ink and products were thoroughly characterized by dynamic light scattering, rheometer, Scanning Electron Microscopy (SEM), and Fourier Transform Infra-Red (FTIR) and Circular Dichroism (CD) spectroscopy. These characterizations confirmed the shape morphology as well as the protein integrity over the process. Further, the effect of various factors on the production were investigated. Our results showed that the concentration of the carrier, chitosan, and the lyoprotectant concentration as well as the extrusion pressure have a significant effect on the particle size. According to CD spectra, SMART ensured Trypsin's secondary structure remained intact regardless of the ink composition and pressure. However, our study revealed that the presence of 5% (w/v) lyoprotectant is essential to maintain the trypsin's proteolytic activity. This study demonstrates, for the first time, the viability of SMART as a single-step efficient process to produce biologics-based stable formulations with a precise control over the particulate morphology which can further be expanded across numerous therapeutic modalities including vaccines and cell/gene therapies.

Clinical progress of therapeutics and vaccines: Rising hope against COVID-19 treatment

Cases of deaths due to COVID-19 (COrona VIrus Disease-19) infection are increasing gradually worldwide. Immense research is ongoing to control this pandemic condition. Continual research outcomes are indicating that therapeutic and prophylactic agents are the possible hope to prevent the pandemic from spreading and to combat this increasing death count. Experience gained from previous coronavirus infections (eg., SARS (Severe Acute Respiratory Syndrome), MERS (Middle Ease Respiratory Syndrome), accumulated clinical knowledge during this pandemic, and research helped to identify a few therapeutic agents for emergency treatment of COVID-19. Thereby, monoclonal antibodies, antivirals, broad-spectrum antimicrobials, immunomodulators, and supplements are being suggested for treatment depending on the stage of the disease. These recommended treatments are authorized under medical supervision in emergency conditions only. Urgent need to control the pandemic condition had resulted in various approaches of repurposing the existing drugs, However, poorly designed clinical trials and associated outcomes do not provide enough evidence to fully approve treatments against COVID-19. So far, World Health Organization (WHO) authorized three vaccines as prophylactic against SARS-CoV-2. Here, we discussed about various therapeutic agents, their clinical trials, and limitations of trials for the management of COVID-19. Further, we have also spotlighted different vaccines in research in combating COVID-19.

Human Serum Albumin as Multifunctional Nanocarrier for Cancer Therapy

Human serum albumin or simply called albumin is a flexible protein employed as a carrier in the fabrication of albumin-based nanocarriers (ANCs) for the administration of cancer therapeutics. Albumin can contribute enhanced tumour specificity, reduced drug induced cytotoxicity and retain concentration of the therapeutically active agent such as drug, peptide, protein, and gene for a prolonged time duration. Nevertheless, apart from cancer management, ANCs are also employed in the diagnosis, imaging, and multimodal cancer therapy. This article figures out salient characteristics, design as well as categories of ANCs in the context of their application in cancer management. In addition, this review article discusses the fabrication methods of ANCs, use of ANCs in gene, cancer, and multimodal therapy along with cancer diagnosis and imaging. Lastly, this review also briefly discusses about (ANCs) formulations, commercial products, and those under clinical testing.

Probing the Role of the Conserved Arg174 in Formate Dehydrogenase by Chemical Modification and Site-Directed Mutagenesis

The reactive adenosine derivative, adenosine 5′-O-[S-(4-hydroxy-2,3-dioxobutyl)]-thiophosphate (AMPS-HDB), contains a dicarbonyl group linked to the purine nucleotide at a position equivalent to the pyrophosphate region of NAD⁺. AMPS-HDB was used as a chemical label towards Candida boidinii formate dehydrogenase (CbFDH). AMPS-HDB reacts covalently with CbFDH, leading to complete inactivation of the enzyme activity. The inactivation kinetics of CbFDH fit the Kitz and Wilson model for time-dependent, irreversible inhibition (K_D = 0.66 ± 0.15 mM, first order maximum rate constant k₃ = 0.198 ± 0.06 min⁻¹). NAD⁺ and NADH protects CbFDH from inactivation by AMPS-HDB, showing the specificity of the reaction. Molecular modelling studies revealed Arg174 as a candidate residue able to be modified by the dicarbonyl group of AMPS-HDB. Arg174 is a strictly conserved residue among FDHs and is located at the Rossmann fold, the common mononucleotide-binding motif of dehydrogenases. Arg174 was replaced by Asn, using site-directed mutagenesis. The mutant enzyme CbFDHArg174Asn was showed to be resistant to inactivation by AMPS-HDB, confirming that the guanidinium group of Arg174 is the target for AMPS-HDB. The CbFDHArg174Asn mutant enzyme exhibited substantial reduced affinity for NAD⁺ and lower thermostability. The results of the study underline the pivotal and multifunctional role of Arg174 in catalysis, coenzyme binding and structural stability of CbFDH.

Self-micro Emulsifying Drug Delivery System “SMEDDS” for Efficient Oral Delivery of Andrographolide

Objective:

Andrographolide has potent anticancer and antimicrobial activity; however, its clinical application has been limited due to its poor water solubility as well as lack of appropriate formulation. The objective of this investigation was to formulate Self–Micro Emulsifying Drug Delivery System (SMEDDS) of andrographolide and explore its oral drug delivery aptitudes.

Methods:

Andrographolide SMEDDS was optimized by ternary phase approach and studied for various in vitro characteristics: Particle size, electron microscopy, polydispersity index, surface charge, dilution effect, pH stability, freeze-thaw effect, dissolution profile and stability studies. Further, antimicrobial and cytotoxic performance of andrographolide SMEDDS were evaluated in MCF–7 breast cancer cell lines and methicillin-resistant microorganisms, respectively.

Results:

An optimized SMEDDS formulation of andrographolide was successfully prepared and evaluated for its drug delivery potential. The solubility of andrographolide in the developed SMEDDS formulation was increased significantly, and the drug loading was enough for making this drug clinically applicable. The andrographolide SMEDDS formulation competitively inhibited the growth of microorganisms and showed enhanced anti–microbial activity against MRSA microorganisms.

Conclusion:

The SMEDDS strategy represents one of the best approaches to deliver andrographolide via oral route, while resolving its solubility limitations.

The potential of dendrimer in delivery of therapeutics for dentistry

Dendrimers are hyperbranched nanoparticle structures along with its surface modifications can to be used in dental biomaterials for biomimetic remineralisation of enamel and dentin. The review highlights the therapeutic applications of dendrimers in the field of dentistry. It addresses the possible mechanisms of enhancement of mechanical properties of adhesives and resins structure. Dendrimers due to its unique construction of possessing inner hydrophobic and outer hydrophilic structure can act as drug carrier for delivery of antimicrobial drugs for treatment of periodontal diseases and at peripheral dental implant areas. Dendrimers due to its hyperbranched structures can provides a unique drug delivery vehicle for delivery of a drug at specific site for sustained release for therapeutic effects. Thus, dendrimers can be one of the most important constituents which can be incorporated in dental biomaterials for better outcomes in dentistry.