Making, Cloning, and the Expression of Human Insulin Genes in Bacteria: The Path to Humulin

Recent advancements in soluble expression of recombinant antibody fragments in microbial host systems

Recombinant fabs dominate the pharmaceutical pipelines today with microbial host systems continuing to be a major contributor toward their production. Escherichia coli is a versatile host for recombinant protein expression due to its simplicity, affordability, and ability to be cultivated at high cell density. It is particularly suitable for non-glycosylated proteins and small proteins. Despite the aforementioned benefits, the use of E. coli as the host for the synthesis of recombinant antibody fragments often suffers from low yield and reduced activity. In most cases, proteins are expressed as inclusion bodies and need to undergo refolding to achieve their active forms and this refolding step is generally low-yielding. In this article, we review the various approaches that researchers have taken to enhance the production of recombinant antibody fragments in E. coli. Molecular biology-oriented approaches such as cloning, chaperone-mediated folding, and host cell screening as well as process optimization involving examination of process parameters, media, and feeding have been addressed.

Evolution of biosynthetic human insulin and its analogues for diabetes management

Hormones play a crucial role in maintaining the normal human physiology. By acting as chemical messengers that facilitate the communication between different organs, tissues and cells of the body hormones assist in responding appropriately to external and internal stimuli that trigger growth, development and metabolic activities of the body. Any abnormalities in the hormonal composition and balance can lead to devastating health consequences. Hormones have been important therapeutic agents since the early 20th century, when it was realized that their exogenous supply could serve as a functional substitution for those hormones which are not produced enough or are completely lacking, endogenously. Insulin, the pivotal anabolic hormone in the body, was used for the treatment of diabetes mellitus, a metabolic disorder due to the absence or intolerance towards insulin, since 1921 and is the trailblazer in hormone therapeutics. At present the largest market share for therapeutic hormones is held by insulin. Many other hormones were introduced into clinical practice following the success with insulin. However, for the six decades following the introduction the first therapeutic hormone, there was no reliable method for producing human hormones. The most common source for hormones were animals, although semisynthetic and synthetic hormones were also developed. However, none of these were optimal because of their allergenicity, immunogenicity, lack of consistency in purity and most importantly, scalability. The advent of recombinant DNA technology was a game changer for hormone therapeutics. This revolutionary molecular biology tool made it possible to synthesize human hormones in microbial cell factories. The approach allowed for the synthesis of highly pure hormones which were structurally and biochemically identical to the human hormones. Further, the fermentation techniques utilized to produce recombinant hormones were highly scalable. Moreover, by employing tools such as site directed mutagenesis along with recombinant DNA technology, it became possible to amend the molecular structure of the hormones to achieve better efficacy and mimic the exact physiology of the endogenous hormone. The first recombinant hormone to be deployed in clinical practice was insulin. It was called biosynthetic human insulin to reflect the biological route of production. Subsequently, the biochemistry of recombinant insulin was modified using the possibilities of recombinant DNA technology and genetic engineering to produce analogues that better mimic physiological insulin. These analogues were tailored to exhibit pharmacokinetic and pharmacodynamic properties of the prandial and basal human insulins to achieve better glycemic control. The present chapter explores the principles of genetic engineering applied to therapeutic hormones by reviewing the evolution of therapeutic insulin and its analogues. It also focuses on how recombinant analogues account for the better management of diabetes mellitus.

Non-Insulin-Based Drug Entities Used to Treat Diabetes Type 2 Disease (T2DM), Based on Natural Products from All Sources

Diabetes type 2 (T2DM) is the non-insulin-linked disease that is now becoming a major problem not only in the West but also in Asia (particularly in China and close geographic areas). Unlike the childhood onset diabetic disease (T1DM), which is effectively due to lack of insulin production and is maintained by insulin injection, T2DM is best thought of as an adult disease often being caused by what is now considered "metabolic syndrome" or the culmination of too many insults to the body, in particular obesity and its "coupled diseases" including heart problems. Its symptoms were described in ancient times not only in Europe but also in Asia and with later (1600s) anecdotal reports from South America. In all cases, the diagnostic was "sweet urine" due to the excretion of large amounts of glucose in the urine. This review covers the non-insulin agents approved from 1990 to 2021 from a historical aspect and discussions of the latest agents and can be considered an extension of the author's previous drug source reviews, but this time concentrating on nominally one disease entity, though metabolic syndrome is a collection of ailments.

Stabilization challenges and aggregation in protein-based therapeutics in the pharmaceutical industry

Protein-based therapeutics have revolutionized the pharmaceutical industry and become vital components in the development of future therapeutics. They offer several advantages over traditional small molecule drugs, including high affinity, potency and specificity, while demonstrating low toxicity and minimal adverse effects. However, the development and manufacturing processes of protein-based therapeutics presents challenges related to protein folding, purification, stability and immunogenicity that should be addressed. These proteins, like other biological molecules, are prone to chemical and physical instabilities. The stability of protein-based drugs throughout the entire manufacturing, storage and delivery process is essential. The occurrence of structural instability resulting from misfolding, unfolding, and modifications, as well as aggregation, poses a significant risk to the efficacy of these drugs, overshadowing their promising attributes. Gaining insight into structural alterations caused by aggregation and their impact on immunogenicity is vital for the advancement and refinement of protein therapeutics. Hence, in this review, we have discussed some features of protein aggregation during production, formulation and storage as well as stabilization strategies in protein engineering and computational methods to prevent aggregation.

Endotoxin accelerates insulin amyloid formation and inactivates insulin signal transduction

AIMS AND OBJECTIVES

The aim of this study is to discuss the influence of endotoxin on insulin amyloid formation, to provide guidance for therapeutic insulin preparation and storage.

MATERIALS AND METHODS

The ThT and ANS binding assays were applied to characterize the dynamics curve of insulin amyloid formation with the presence or absence of endotoxin. The morphological structures of intermediate and mature insulin fibrils were observed with SEM and TEM. Secondary structural changes of insulin during fibriliation were examined with CD, FTIR and Raman spectral analysis. The cytotoxic effects of oligomeric and amyloidogenic insulin aggregates were detected using a cck-8 cell viability assay kit. The influence of endotoxin on insulin efficacy was analyzed by monitoring the activation of insulin signal transduction.

KEY FINDINGS

ThT analysis showed that endotoxin, regardless of species, accelerated insulin fibrils formation in a dose-dependent manner, as observed with a shorter lag phase. ANS binding assay demonstrated endotoxin provoked the exposure of insulin hydrophobic patches. The results of SEM and TEM data displayed that endotoxin drove insulin to cluster into dense and viscous form, with thicker and stronger filaments. Based on CD, FTIR and Raman spectra, endotoxin promoted the transition of α-helix to random coil and β-strand secondary structures during insulin aggregation. Insulins in both oligomeric and amyloidogenic forms were cytotoxic to HepG2 cells, with the former being more severe. Finally, the efficacy of endotoxin treated insulin obviously decreased.

SIGNIFICANCE

Our studies revealed that endotoxin disrupts the structural integrity of insulin and promotes its amyloidosis. These findings offered theoretical guidance for insulin storage and safe utilization, as well as pointing up a new direction for insulin resistance research.

Insulin Therapy for the Management of Diabetes Mellitus: A Narrative Review of Innovative Treatment Strategies

The discovery of insulin was presented to the international medical community on May 3, 1922. Since then, insulin has become one of the most effective pharmacological agents used to treat type 1 and type 2 diabetes mellitus. However, the initiation and intensification of insulin therapy is often delayed in people living with type 2 diabetes due to numerous challenges associated with daily subcutaneous administration. Reducing the frequency of injections, using insulin pens instead of syringes and vials, simplifying treatment regimens, or administering insulin through alternative routes may help improve adherence to and persistence with insulin therapy among people living with diabetes. As the world commemorates the centennial of the commercialization of insulin, the aims of this article are to provide an overview of insulin therapy and to summarize clinically significant findings from phase 3 clinical trials evaluating less frequent dosing of insulin and the non-injectable administration of insulin.

Amplifying gene expression with RNA-targeted therapeutics

Many diseases are caused by insufficient expression of mutated genes and would benefit from increased expression of the corresponding protein. However, in drug development, it has been historically easier to develop drugs with inhibitory or antagonistic effects. Protein replacement and gene therapy can achieve the goal of increased protein expression but have limitations. Recent discoveries of the extensive regulatory networks formed by non-coding RNAs offer alternative targets and strategies to amplify the production of a specific protein. In addition to RNA-targeting small molecules, new nucleic acid-based therapeutic modalities that allow highly specific modulation of RNA-based regulatory networks are being developed. Such approaches can directly target the stability of mRNAs or modulate non-coding RNA-mediated regulation of transcription and translation. This Review highlights emerging RNA-targeted therapeutics for gene activation, focusing on opportunities and challenges for translation to the clinic.

Virology under the Microscope-a Call for Rational Discourse

Viruses have brought humanity many challenges: respiratory infection, cancer, neurological impairment and immunosuppression to name a few. Virology research over the last 60+ years has responded to reduce this disease burden with vaccines and antivirals. Despite this long history, the COVID-19 pandemic has brought unprecedented attention to the field of virology. Some of this attention is focused on concern about the safe conduct of research with human pathogens. A small but vocal group of individuals has seized upon these concerns - conflating legitimate questions about safely conducting virus-related research with uncertainties over the origins of SARS-CoV-2. The result has fueled public confusion and, in many instances, ill-informed condemnation of virology. With this article, we seek to promote a return to rational discourse. We explain the use of gain-of-function approaches in science, discuss the possible origins of SARS-CoV-2 and outline current regulatory structures that provide oversight for virological research in the United States. By offering our expertise, we - a broad group of working virologists - seek to aid policy makers in navigating these controversial issues. Balanced, evidence-based discourse is essential to addressing public concern while maintaining and expanding much-needed research in virology.

Virology under the Microscope-a Call for Rational Discourse

Viruses have brought humanity many challenges: respiratory infection, cancer, neurological impairment and immunosuppression to name a few. Virology research over the last 60+ years has responded to reduce this disease burden with vaccines and antivirals. Despite this long history, the COVID-19 pandemic has brought unprecedented attention to the field of virology. Some of this attention is focused on concern about the safe conduct of research with human pathogens. A small but vocal group of individuals has seized upon these concerns - conflating legitimate questions about safely conducting virus-related research with uncertainties over the origins of SARS-CoV-2. The result has fueled public confusion and, in many instances, ill-informed condemnation of virology. With this article, we seek to promote a return to rational discourse. We explain the use of gain-of-function approaches in science, discuss the possible origins of SARS-CoV-2 and outline current regulatory structures that provide oversight for virological research in the United States. By offering our expertise, we - a broad group of working virologists - seek to aid policy makers in navigating these controversial issues. Balanced, evidence-based discourse is essential to addressing public concern while maintaining and expanding much-needed research in virology.

Virology under the Microscope-a Call for Rational Discourse

Viruses have brought humanity many challenges: respiratory infection, cancer, neurological impairment and immunosuppression to name a few. Virology research over the last 60+ years has responded to reduce this disease burden with vaccines and antivirals. Despite this long history, the COVID-19 pandemic has brought unprecedented attention to the field of virology. Some of this attention is focused on concern about the safe conduct of research with human pathogens. A small but vocal group of individuals has seized upon these concerns - conflating legitimate questions about safely conducting virus-related research with uncertainties over the origins of SARS-CoV-2. The result has fueled public confusion and, in many instances, ill-informed condemnation of virology. With this article, we seek to promote a return to rational discourse. We explain the use of gain-of-function approaches in science, discuss the possible origins of SARS-CoV-2 and outline current regulatory structures that provide oversight for virological research in the United States. By offering our expertise, we - a broad group of working virologists - seek to aid policy makers in navigating these controversial issues. Balanced, evidence-based discourse is essential to addressing public concern while maintaining and expanding much-needed research in virology.

Bioactive VEGF-C from E. coli

Vascular endothelial growth factor-C (VEGF-C) stimulates lymphatic vessel growth in transgenic models, via viral gene delivery, and as a recombinant protein. Expressing eukaryotic proteins like VEGF-C in bacterial cells has limitations, as these cells lack specific posttranslational modifications and provisions for disulfide bond formation. However, given the cost and time savings associated with bacterial expression systems, there is considerable value in expressing VEGF-C using bacterial cells. We identified two approaches that result in biologically active Escherichia coli-derived VEGF-C. Expectedly, VEGF-C expressed from a truncated cDNA became bioactive after in vitro folding from inclusion bodies. Given that VEGF-C is one of the cysteine-richest growth factors in humans, it was unclear whether known methods to facilitate correct cysteine bond formation allow for the direct expression of bioactive VEGF-C in the cytoplasm. By fusing VEGF-C to maltose-binding protein and expressing these fusions in the redox-modified cytoplasm of the Origami (DE3) strain, we could recover biological activity for deletion mutants lacking the propeptides of VEGF-C. This is the first report of a bioactive VEGF growth factor obtained from E. coli cells circumventing in-vitro folding.

Prediction of Drug–Target Interaction Using Dual-Network Integrated Logistic Matrix Factorization and Knowledge Graph Embedding

Nowadays, drug–target interactions (DTIs) prediction is a fundamental part of drug repositioning. However, on the one hand, drug–target interactions prediction models usually consider drugs or targets information, which ignore prior knowledge between drugs and targets. On the other hand, models incorporating priori knowledge cannot make interactions prediction for under-studied drugs and targets. Hence, this article proposes a novel dual-network integrated logistic matrix factorization DTIs prediction scheme (Ro-DNILMF) via a knowledge graph embedding approach. This model adds prior knowledge as input data into the prediction model and inherits the advantages of the DNILMF model, which can predict under-studied drug–target interactions. Firstly, a knowledge graph embedding model based on relational rotation (RotatE) is trained to construct the interaction adjacency matrix and integrate prior knowledge. Secondly, a dual-network integrated logistic matrix factorization prediction model (DNILMF) is used to predict new drugs and targets. Finally, several experiments conducted on the public datasets are used to demonstrate that the proposed method outperforms the single base-line model and some mainstream methods on efficiency.

[The insulin receptor discovery is 50 years old - A review of achieved progress]

The isolation of insulin from the pancreas and its purification to a degree permitting its safe administration to type 1 diabetic patients were accomplished 100 years ago at the University of Toronto by Banting, Best, Collip and McLeod and constitute undeniably one of the major medical therapeutic revolutions, recognized by the attribution of the 1923 Nobel Prize in Physiology or Medicine to Banting and McLeod. The clinical spin off was immediate as well as the internationalization of insulin's commercial production. The outcomes regarding basic research were much slower, in particular regarding the molecular mechanisms of insulin action on its target cells. It took almost a half-century before the determination of the tri-dimensional structure of insulin in 1969 and the characterization of its cell receptor in 1970-1971. The demonstration that the insulin receptor is in fact an enzyme named tyrosine kinase came in the years 1982-1985, and the crystal structure of the intracellular kinase domain 10 years later. The crystal structure of the first intracellular kinase substrate (IRS-1) in 1991 paved the way for the elucidation of the intracellular signalling pathways but it took 15 more years to obtain the complete crystal structure of the extracellular receptor domain (without insulin) in 2006. Since then, the determination of the structure of the whole insulin-receptor complex in both the inactive and activated states has made considerable progress, not least due to recent improvement in the resolution power of cryo-electron microscopy. I will here review the steps in the development of the concept of hormone receptor, and of our knowledge of the structure and molecular mechanism of activation of the insulin receptor.

A Comprehensive Review of the Evolution of Insulin Development and Its Delivery Method

The year 2021 marks the 100th anniversary of the momentous discovery of insulin. Through years of research and discovery, insulin has evolved from poorly defined crude extracts of animal pancreas to recombinant human insulin and analogues that can be prescribed and administered with high accuracy and efficacy. However, there are still many challenges ahead in clinical settings, particularly with respect to maintaining optimal glycemic control whilst minimizing the treatment-related side effects of hypoglycemia and weight gain. In this review, the chronology of the development of rapid-acting, short-acting, intermediate-acting, and long-acting insulin analogues, as well as mixtures and concentrated formulations that offer the potential to meet this challenge, are summarized. In addition, we also summarize the latest advancements in insulin delivery methods, along with advancement to clinical trials. This review provides insights on the development of insulin treatment for diabetes mellitus that may be useful for clinicians in meeting the needs of their individual patients. However, it is important to note that as of now, none of the new technologies mentioned have superseded the existing method of subcutaneous administration of insulin.

The Noble and Often Nobel Role Played by Insulin-Focused Research in Modern Medicine

Since diabetes was first described over 3,000 years ago, clinicians and scientists alike have sought ever improving treatments en route to a cure. As we approach the 100th anniversary of insulin's first therapeutic use, this article will recount the glorious history associated with research surrounding insulin's isolation, purification, cloning, and subsequent modification. The discovery path we will relate tells the story of many relentless and passionate investigators pursuing ground-breaking research. The fruits of their labor include several Nobel Prizes, new technology, and, more importantly, ever improving treatments for one of humankind's greatest medical scourges.

Insulin: A 100-Year-Old Discovery With a Fascinating History

Diabetes has been known since antiquity. We present here a historical perspective on the concepts and ideas regarding the physiopathology of the disease, on the progressive focus on the pancreas, in particular on the islets discovered by Langerhans in 1869, leading to the iconic experiment of Minkowski and von Mering in 1889 showing that pancreatectomy in a dog induced polyuria and diabetes mellitus. Subsequently, multiple investigators searched for the active substance of the pancreas and some managed to produce extracts that lowered blood glucose and decreased polyuria in pancreatectomized dogs but were too toxic to be administered to patients. The breakthrough came 100 years ago, when the team of Frederick Banting, Charles Best, and James Collip working in the Department of Physiology headed by John Macleod at the University of Toronto managed to obtain pancreatic extracts that could be used to treat patients and rescue them from the edge of death by starvation, the only treatment then available. This achievement was quickly recognized by the Nobel Prize in Physiology or Medicine to Banting and Macleod in 1923. At 32, Banting remains the youngest awardee of this prize. Here we discuss the work that led to the discovery and its main breakthroughs, the human characters involved in an increasingly dysfunctional relationship, the controversies that followed the Nobel Prize, and the debate as to who actually "discovered" insulin. We also discuss the early commercial development and progress in insulin crystallization in the decade or so following the Nobel Prize.

A Century of Progress in Diabetes Care with Insulin: A History of Innovations and Foundation for the Future

The year 2021 marks the 100th anniversary of the discovery of insulin, which has greatly changed the lives of people with diabetes and become a cornerstone of advances in medical science. A rapid bench-to-bedside application of the lifesaving pancreatic extract and its immediate commercialization was the result of a promising idea, positive drive, perseverance, and collaboration of Banting and colleagues. As one of the very few proteins isolated in a pure form at that time, insulin also played a key role in the development of important methodologies and in the beginning of various fields of modern science. Since its discovery, insulin has evolved continuously to optimize the care of people with diabetes. Since the 1980s, recombinant DNA technology has been employed to engineer insulin analogs by modifying their amino acid sequence, which has resulted in the production of insulins with various profiles that are currently used. However, unmet needs in insulin treatment still exist, and several forms of future insulins are under development. In this review, we discuss the past, present, and future of insulin, including a history of ceaseless innovations and collective intelligence. We believe that this story will be a solid foundation and an unerring guide for the future.

Apolipoprotein and LRP1-Based Peptides as New Therapeutic Tools in Atherosclerosis

Apolipoprotein (Apo)-based mimetic peptides have been shown to reduce atherosclerosis. Most of the ApoC-II and ApoE mimetics exert anti-atherosclerotic effects by improving lipid profile. ApoC-II mimetics reverse hypertriglyceridemia and ApoE-based peptides such as Ac-hE18A-NH2 reduce cholesterol and triglyceride (TG) levels in humans. Conversely, other classes of ApoE and ApoA-I mimetic peptides and, more recently, ApoJ and LRP1-based peptides, exhibit several anti-atherosclerotic actions in experimental models without influencing lipoprotein profile. These other mimetic peptides display at least one atheroprotective mechanism such as providing LDL stability against mechanical modification or conferring protection against the action of lipolytic enzymes inducing LDL aggregation in the arterial intima. Other anti-atherosclerotic effects exerted by these peptides also include protection against foam cell formation and inflammation, and induction of reverse cholesterol transport. Although the underlying mechanisms of action are still poorly described, the recent findings suggest that these mimetics could confer atheroprotection by favorably influencing lipoprotein function rather than lipoprotein levels. Despite the promising results obtained with peptide mimetics, the assessment of their stability, atheroprotective efficacy and tissue targeted delivery are issues currently under progress.