Improving Insulin with Staples♦ : Supramolecular Protein Engineering. Design of Zinc-stapled Insulin Hexamers as a Long Acting Depot
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PROVIDER: S-EPMC2852985 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Bottom-up control of supramolecular protein assembly can provide a therapeutic nanobiotechnology. We demonstrate that the pharmacological properties of insulin can be enhanced by design of "zinc staples" between hexamers. Paired (i, i+4) His substitutions were introduced at an alpha-helical surface. The crystal structure contains both classical axial zinc ions and novel zinc ions at hexamer-hexamer interfaces. Although soluble at pH 4, the combined electrostatic effects of the substitutions and bridging zinc ions cause isoelectric precipitation at neutral pH. Following subcutaneous injection in a diabetic rat, the analog effected glycemic control with a time course similar to that of long acting formulation Lantus. Relative to Lantus, however, the analog discriminates at least 30-fold more stringently between the insulin receptor and mitogenic insulin-like growth factor receptor. Because aberrant mitogenic signaling may be associated with elevated cancer risk, such enhanced specificity may improve safety. Zinc stapling provides a general strategy to modify the pharmacokinetic and biological properties of a subcutaneous protein depot.
| S-EPMC2852910 | biostudies-literature
Project description:The kinetic stability of insulin hexamers containing two metal ions was investigated by means of hybridization experiments. Insulin was covalently labeled at the N(epsilon)-amino group of Lys(B29) by a fluorescence donor and acceptor group, respectively. The labels neither affect the tertiary structure nor interfere with self-association. Equimolar solutions of pure donor and acceptor insulin hexamers were mixed, and the hybridization was monitored by fluorescence resonance energy transfer. With the total insulin concentration remaining constant and the association/dissociation equilibria unperturbed, the subunit interchange between hexamers is an entropy-driven relaxation process that ends at statistical distribution of the labels over 16 types of hexamers differing by their composition. The analytical description of the interchange kinetics on the basis of a plausible model has yielded the first experimental values for the lifetime of the hexamers. The lifetime is reciprocal to the product of the concentration of the exchanged species and the interchange rate constant: tau = 1/(c. k). Measured for different concentrations, temperatures, metal ions, and ligand-dependent conformational states, the lifetime was found to cover a range from minutes for T(6) to days for R(6) hexamers. The approach can be used under an unlimited variety of conditions. The information it provides is of obvious relevance for the handling, storage, and pharmacokinetic properties of insulin preparations.
| S-EPMC1300452 | biostudies-other
Project description:Previously, we reported the conversion of the 12-mer linear and cell-impermeable peptide CAI to a cell-penetrating peptide NYAD-1 by using an i,i + 4 hydrocarbon stapling technique and confirmed its binding to the C-terminal domain (CTD) of the HIV-1 capsid (CA) protein with an improved affinity (K(d) ~ 1 ?M) compared to CAI (K(d) ~ 15 ?M). NYAD-1 disrupts the formation of both immature- and mature-like virus particles in in vitro and cell-based assembly assays. In addition, it displays potent anti-HIV-1 activity in cell culture against a range of laboratory-adapted and primary HIV-1 isolates.In this report, we expanded the study to i,i + 7 hydrocarbon-stapled peptides to delineate their mechanism of action and antiviral activity. We identified three potent inhibitors, NYAD-36, -66 and -67, which showed strong binding to CA in NMR and isothermal titration calorimetry (ITC) studies and disrupted the formation of mature-like particles. They showed typical ?-helical structures and penetrated cells; however, the cell penetration was not as efficient as observed with the i,i + 4 peptides. Unlike NYAD-1, the i,i + 7 peptides did not have any effect on virus release; however, they impaired Gag precursor processing. HIV-1 particles produced in the presence of these peptides displayed impaired infectivity. Consistent with an effect on virus entry, selection for viral resistance led to the emergence of two mutations in the gp120 subunit of the viral envelope (Env) glycoprotein, V120Q and A327P, located in the conserved region 1 (C1) and the base of the V3 loop, respectively.The i,i + 7 stapled peptides derived from CAI unexpectedly target both CA and the V3 loop of gp120. This dual-targeted activity is dependent on their ability to penetrate cells as well as their net charge. This mechanistic revelation will be useful in further modifying these peptides as potent anti-HIV-1 agents.
| S-EPMC3842668 | biostudies-literature
Project description:Amyloids are highly organized protein aggregates that are associated with both neurodegenerative diseases such as Alzheimer disease and benign functions like skin pigmentation. Amyloids self-polymerize in a nucleation-dependent manner by recruiting their soluble protein/peptide counterpart and are stable against harsh physical, chemical, and biochemical conditions. These extraordinary properties make amyloids attractive for applications in nanotechnology. Here, we suggest the use of amyloids in the formulation of long-acting drugs. It is our rationale that amyloids have the properties required of a long-acting drug because they are stable depots that guarantee a controlled release of the active peptide drug from the amyloid termini. This concept is tested with a family of short- and long-acting analogs of gonadotropin-releasing hormone (GnRH), and it is shown that amyloids thereof can act as a source for the sustained release of biologically active peptides.
| S-EPMC2225439 | biostudies-literature
Project description:OBJECTIVE:Mathematical models of insulin absorption have been used to predict plasma insulin concentrations after administration, but few are specifically applicable to insulin glargine, which precipitates subcutaneously after injection. MATERIALS AND METHODS:The formation and redissolution of subcutaneous depots of insulin glargine 100 U/mL (Gla-100) and insulin glargine 300 U/mL (Gla-300) are modeled. Surface-area-dependent redissolution is introduced to established diffusion and absorption pathways, and pharmacokinetic (PK) profiles are simulated and subsequently validated using experimental data from euglycemic glucose clamp studies. Simulations are used to predict the PK effect of adapting the timing of once-daily insulin injections and of switching from one insulin product to the other. -Results: Simulated PK profiles resemble those previously observed in clinical trials, with Gla-300 providing more gradual and prolonged release of Gla-300 vs. Gla-100, owing to a more compact depot. The predicted PK profile of Gla-300 shows less fluctuation in plasma insulin concentrations than that of Gla-100, and may be better suited to adapting the timing of daily injections to account for variation in daily activities. Simulating a switch from one insulin glargine product to the other results in temporary alteration of previous steady state, but this is regained within ~ 3 days. CONCLUSION:This study suggests that PK differences between Gla-300 and Gla-100 are a product of the more compact Gla-300 depot and its smaller surface area. The model employed also allowed estimation of insulin glargine concentrations when varying the time interval between injections as well as when switching from one insulin glargine product to the other.?.
| S-EPMC6298133 | biostudies-literature
Project description:Abstract This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To assess the effects of ultra?long acting insulin compared with long?acting insulin in patients with T1DM.
| S-EPMC6513582 | biostudies-literature
Project description:Two-dimensional sheet-like supramolecules have attracted much attention from the viewpoints of their potential application as functional (nano)materials due to unique physical and chemical properties. One of the supramolecular sheet-like nanostructures in nature is visible in the self-assemblies of bacteriochlorophyll-c-f pigments inside chlorosomes, which are major components in the antenna systems of photosynthetic green bacteria. Herein, we report artificial chlorosomal supramolecular nanosheets prepared by the self-assembly of a synthetic zinc 31-methoxy-chlorophyll derivative having amide and urea groups in the substituent at the 17-position. The semi-synthetic zinc chlorophyll derivative kinetically formed dimeric species and transformed into more thermodynamically stable chlorosomal J-aggregates in the solid state. The kinetically and thermodynamically formed self-assemblies had particle-like and sheet-like supramolecular nanostructures, respectively. The resulting nanosheets of biomimetic chlorosomal J-aggregates had flat surfaces and well-ordered supramolecular structures. The artificial sheet-like nanomaterial mimicking chlorosomal bacteriochlorophyll-c-f J-aggregates was first constructed by the model molecule, and is potentially useful for various applications including artificial light-harvesting antennas and photosyntheses.
| S-EPMC6773735 | biostudies-literature
Project description:ImportanceCardiovascular events and mortality are the principal causes of excess mortality and health care costs for people with type 2 diabetes. No large studies have specifically compared long-acting insulin alone with long-acting plus short-acting insulin with regard to cardiovascular outcomes.ObjectiveTo compare cardiovascular events and mortality in adults with type 2 diabetes receiving long-acting insulin who do or do not add short-acting insulin.Design, setting, and participantsThis retrospective cohort study emulated a randomized experiment in which adults with type 2 diabetes who experienced a qualifying glycated hemoglobin A1c (HbA1c) level of 6.8% to 8.5% with long-acting insulin were randomized to continuing treatment with long-acting insulin (LA group) or adding short-acting insulin within 1 year of the qualifying HbA1c level (LA plus SA group). Retrospective data in 4 integrated health care delivery systems from the Health Care Systems Research Network from January 1, 2005, to December 31, 2013, were used. Analysis used inverse probability weighting estimation with Super Learner for propensity score estimation. Analyses took place from April 1, 2018, to June 30, 2019.ExposuresLong-acting insulin alone or with added short-acting insulin within 1 year from the qualifying HbA1c level.Main outcomes and measuresMortality, cardiovascular mortality, acute myocardial infarction, stroke, and hospitalization for heart failure.ResultsAmong 57 278 individuals (39 279 with data on cardiovascular mortality) with a mean (SD) age of 60.6 (11.5) years, 53.6% men, 43.5% non-Hispanic White individuals, and 4 years of follow-up (median follow-up of 11 [interquartile range, 5-20] calendar quarters), the LA plus SA group was associated with increased all-cause mortality compared with the LA group (hazard ratio, 1.27; 95% CI, 1.05-1.49) and a decreased risk of acute myocardial infarction (hazard ratio, 0.89; 95% CI, 0.81-0.97). Treatment with long-acting plus short-acting insulin was not associated with increased risks of congestive heart failure, stroke, or cardiovascular mortality.Conclusions and relevanceFindings of this retrospective cohort study suggested an increased risk of all-cause mortality and a decreased risk of acute myocardial infarction for the LA plus SA group compared with the LA group. Given the lack of an increase in major cardiovascular events or cardiovascular mortality, the increased all-cause mortality with long-acting plus short-acting insulin may be explained by noncardiovascular events or unmeasured confounding.
| S-EPMC8463942 | biostudies-literature