scholarly journals Inhaled Insulin Forms Toxic Pulmonary Amyloid Aggregates

Endocrinology ◽  
2010 ◽  
Vol 151 (10) ◽  
pp. 4717-4724 ◽  
Author(s):  
Cristian A. Lasagna-Reeves ◽  
Audra L. Clos ◽  
Terumi Midoro-Hiriuti ◽  
Randall M. Goldblum ◽  
George R. Jackson ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Protein Misfolding ◽  
Diabetic Patients ◽  
Amyloid Formation ◽  
Pulmonary Tissue ◽  
Inhaled Insulin ◽  
Parkinson’S Diseases ◽  
Pulmonary Air Flow

It is well known that interfaces, such as polar-nonpolar or liquid-air, play a key role in triggering protein aggregation in vitro, in particular the aggregation of peptides and proteins with the predisposition of misfolding and aggregation. Here we show that the interface present in the lungs predisposes the lungs to form aggregation of inhaled insulin. Insulin inhalers were introduced, and a large number of diabetic patients have used them. Although inhalers were safe and effective, decreases in pulmonary capacity have been reported in response to inhaled insulin. We hypothesize that the lung air-tissue interface provides a template for the aggregation of inhaled insulin. Our studies were designed to investigate the harmful potential that inhaled insulin has in pulmonary tissue in vivo, through an amyloid formation mechanism. Our data demonstrate that inhaled insulin rapidly forms amyloid in the lungs causing a significant reduction in pulmonary air flow. Our studies exemplify the importance that interfaces play in protein aggregation in vivo, illustrating the potential aggregation of inhaled proteins and the formation of amyloid deposits in the lungs. These insulin deposits resemble the amyloid structures implicated in protein misfolding disorders, such as Alzheimer’s and Parkinson’s diseases, and could as well be deleterious in nature.

scholarly journals Kinetic analysis reveals the rates and mechanisms of protein aggregation in a multicellular organism

2020 ◽  
Author(s):  
Tessa Sinnige ◽  
Georg Meisl ◽  
Thomas C. T. Michaels ◽  
Michele Vendruscolo ◽  
Tuomas P.J. Knowles ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Protein Misfolding ◽  
Molecular Model ◽  
Kinetic Studies ◽  
Living Organism ◽  
Model Systems ◽  
Amyloid Formation ◽  
Wide Range

AbstractThe accumulation of insoluble protein aggregates containing amyloid fibrils has been observed in many different human protein misfolding diseases1,2, and their pathological features have been recapitulated in diverse model systems3. In vitro kinetic studies have provided a quantitative understanding of how the fundamental molecular level processes of nucleation and growth lead to amyloid formation4. However, it is not yet clear to what extent these basic biophysical processes translate to amyloid formation in vivo, given the complexity of the cellular and organismal environment. Here we show that the aggregation of a fluorescently tagged polyglutamine (polyQ) protein into µm-sized inclusions in the muscle tissue of living C. elegans can be quantitatively described by a molecular model where stochastic nucleation occurs independently in each cell, followed by rapid aggregate growth. Global fitting of the image-based aggregation kinetics reveals a nucleation rate corresponding to 0.01 h-1 per cell at 1 mM intracellular protein concentration, and shows that the intrinsic stochasticity of nucleation accounts for a significant fraction of the observed animal-to-animal variation. Our results are consistent with observations for the aggregation of polyQ proteins in vitro5 and in cell culture6, and highlight how nucleation events control the overall progression of aggregation in the organism through the spatial confinement into individual cells. The key finding that the biophysical principles associated with protein aggregation in small volumes remain the governing factors, even in the complex environment of a living organism, will be critical for the interpretation of in vivo data from a wide range of protein aggregation diseases.

scholarly journals Biophysical studies of protein misfolding and aggregation in in vivo models of Alzheimer's and Parkinson's diseases

2020 ◽  
Vol 53 ◽  
Author(s):  
Tessa Sinnige ◽  
Karen Stroobants ◽  
Christopher M. Dobson ◽  
Michele Vendruscolo
Keyword(s):  
Protein Misfolding ◽  
Molecular Mechanisms ◽  
Amyloid Β ◽  
Therapeutic Interventions ◽  
In Vivo Models ◽  
Disease Modifying Drugs ◽  
Parkinson’S Diseases ◽  
Protein Misfolding And Aggregation

Abstract Neurodegenerative disorders, including Alzheimer's (AD) and Parkinson's diseases (PD), are characterised by the formation of aberrant assemblies of misfolded proteins. The discovery of disease-modifying drugs for these disorders is challenging, in part because we still have a limited understanding of their molecular origins. In this review, we discuss how biophysical approaches can help explain the formation of the aberrant conformational states of proteins whose neurotoxic effects underlie these diseases. We discuss in particular models based on the transgenic expression of amyloid-β (Aβ) and tau in AD, and α-synuclein in PD. Because biophysical methods have enabled an accurate quantification and a detailed understanding of the molecular mechanisms underlying protein misfolding and aggregation in vitro, we expect that the further development of these methods to probe directly the corresponding mechanisms in vivo will open effective routes for diagnostic and therapeutic interventions.

scholarly journals The novel chaperone protein SRCP1 reduces insoluble SOD1 protein in vivo without extending ALS mouse lifespan

2020 ◽  
Author(s):  
Ian W. Luecke ◽  
Gloria Lin ◽  
Stephanie Santarriaga ◽  
K. Matthew Scaglione ◽  
Allison D. Ebert
Keyword(s):  
Protein Aggregation ◽  
Motor Neurons ◽  
Protein Misfolding ◽  
Protein Quality ◽  
Therapeutic Potential ◽  
Dependent Manner ◽  
Insoluble Protein ◽  
Chaperone Protein

AbstractProtein misfolding and aggregation are shared features of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), and protein quality control disruption contributes to neuronal toxicity. Therefore, reducing protein aggregation could hold therapeutic potential. We previously identified a novel chaperone protein, serine-rich chaperone protein 1 (SRCP1), that effectively prevents protein aggregation in cell culture and zebrafish models of Huntington’s disease. Here we tested whether this benefit extends to aggregated proteins found in ALS. We used viral-mediated expression of SRCP1 in in vitro and in vivo models of ALS. We found that SRCP1 reduced insoluble SOD1 protein levels in HEK293T cells overexpressing either the A4V or G93R mutant SOD1. However, the reduction of insoluble protein was not observed in either mutant C9orf72 or SOD1 ALS iPSC-derived motor neurons infected with a lentivirus expressing SRCP1. SOD1 G93A ALS mice injected with AAV-SRCP1 showed a small but significant reduction in insoluble and soluble SOD1 in both the brain and spinal cord, but SRCP1 expression did not improve mouse survival. These data indicate that SRCP1 likely reduces insoluble protein burden in a protein and/or context-dependent manner indicating a need for additional insight into SRCP1 function and therapeutic potential.

scholarly journals α-Synuclein promotes IAPP fibril formation in vitro and β-cell amyloid formation in vivo in mice

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Marija Mucibabic ◽  
Pär Steneberg ◽  
Emmelie Lidh ◽  
Jurate Straseviciene ◽  
Agnieszka Ziolkowska ◽  
...  
Keyword(s):  
Protein Misfolding ◽  
Alpha Synuclein ◽  
Fibril Formation ◽  
Amyloid Formation ◽  
Β Cells ◽  
Β Cell ◽  
Islet Amyloid ◽  
Misfolding Diseases

AbstractType 2 diabetes (T2D), alike Parkinson’s disease (PD), belongs to the group of protein misfolding diseases (PMDs), which share aggregation of misfolded proteins as a hallmark. Although the major aggregating peptide in β-cells of T2D patients is Islet Amyloid Polypeptide (IAPP), alpha-synuclein (αSyn), the aggregating peptide in substantia nigra neurons of PD patients, is expressed also in β-cells. Here we show that αSyn, encoded by Snca, is a component of amyloid extracted from pancreas of transgenic mice overexpressing human IAPP (denoted hIAPPtg mice) and from islets of T2D individuals. Notably, αSyn dose-dependently promoted IAPP fibril formation in vitro and tail-vein injection of αSyn in hIAPPtg mice enhanced β-cell amyloid formation in vivo whereas β-cell amyloid formation was reduced in hIAPPtg mice on a Snca −/− background. Taken together, our findings provide evidence that αSyn and IAPP co-aggregate both in vitro and in vivo, suggesting a role for αSyn in β-cell amyloid formation.

scholarly journals The Aggregation of Huntingtin and α-Synuclein

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
María Elena Chánez-Cárdenas ◽  
Edgar Vázquez-Contreras
Keyword(s):  
Protein Aggregation ◽  
Protein Interactions ◽  
Protein Function ◽  
Driving Forces ◽  
Chemical Compounds ◽  
Origin And Evolution ◽  
Parkinson’S Diseases ◽  
Biomaterial Science

Huntington’s and Parkinson’s diseases are neurodegenerative disorders associated with unusual protein interactions. Although the origin and evolution of these diseases are completely different, characteristic deposits of protein aggregates (huntingtin and α-synuclein resp.), are a common feature in both diseases. After these observations, many studies are performed with both proteins. Some of them try to understand the nature and driving forces of the aggregation process; others try to find a correlation between the genetic and failure in protein function. Finally with the combination of both approaches, it was proposed that possible strategies deal with pathologic aggregation. Unfortunately, if protein aggregation is a cause or a consequence of the neurodegeneration observed in these pathologies, it is still debatable. This paper describes the process of aggregation of two proteins: huntingtin and α synuclein. The characteristics of the aggregation reaction of these proteins have been followed with novel methods both in vivo and in vitro; these studies include both the combination with other proteins and the presence of various chemical compounds. The ultimate goal of this study was to summarize recent findings on protein aggregation and its possible role as a therapeutic target in neurodegenerative diseases and their role in biomaterial science.

scholarly journals Bacterial production and direct functional screening of expanded molecular libraries for discovering inhibitors of protein aggregation

2019 ◽  
Vol 5 (10) ◽  
pp. eaax5108 ◽  
Author(s):  
Dafni C. Delivoria ◽  
Sean Chia ◽  
Johnny Habchi ◽  
Michele Perni ◽  
Ilias Matis ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Early Stage ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Functional Screening ◽  
Parkinson’S Diseases ◽  
Aggregation Inhibitors ◽  
Molecular Libraries

Protein misfolding and aggregation are associated with a many human disorders, including Alzheimer’s and Parkinson’s diseases. Toward increasing the effectiveness of early-stage drug discovery for these conditions, we report a bacterial platform that enables the biosynthesis of molecular libraries with expanded diversities and their direct functional screening for discovering protein aggregation inhibitors. We illustrate this approach by performing, what is to our knowledge, the largest functional screen of small-size molecular entities described to date. We generated a combinatorial library of ~200 million drug-like, cyclic peptides and rapidly screened it for aggregation inhibitors against the amyloid-β peptide (Aβ42), linked to Alzheimer’s disease. Through this procedure, we identified more than 400 macrocyclic compounds that efficiently reduce Aβ42 aggregation and toxicity in vitro and in vivo. Finally, we applied a combination of deep sequencing and mutagenesis analyses to demonstrate how this system can rapidly determine structure-activity relationships and define consensus motifs required for bioactivity.

scholarly journals Kinetic analysis reveals that independent nucleation events determine the progression of polyglutamine aggregation in C. elegans

2021 ◽  
Vol 118 (11) ◽  
pp. e2021888118
Author(s):  
Tessa Sinnige ◽  
Georg Meisl ◽  
Thomas C. T. Michaels ◽  
Michele Vendruscolo ◽  
Tuomas P. J. Knowles ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Molecular Model ◽  
Kinetic Studies ◽  
Living Organism ◽  
Amyloid Formation ◽  
Complex Environment ◽  
C Elegans ◽  
Wide Range

Protein aggregation is associated with a wide range of degenerative human diseases with devastating consequences, as exemplified by Alzheimer’s, Parkinson’s, and Huntington’s diseases. In vitro kinetic studies have provided a mechanistic understanding of the aggregation process at the molecular level. However, it has so far remained largely unclear to what extent the biophysical principles of amyloid formation learned in vitro translate to the complex environment of living organisms. Here, we take advantage of the unique properties of a Caenorhabditis elegans model expressing a fluorescently tagged polyglutamine (polyQ) protein, which aggregates into discrete micrometer-sized inclusions that can be directly visualized in real time. We provide a quantitative analysis of protein aggregation in this system and show that the data are described by a molecular model where stochastic nucleation occurs independently in each cell, followed by rapid aggregate growth. Global fitting of the image-based aggregation kinetics reveals a nucleation rate corresponding to 0.01 h−1 per cell at 1 mM intracellular protein concentration, and shows that the intrinsic molecular stochasticity of nucleation accounts for a significant fraction of the observed animal-to-animal variation. Our results highlight how independent, stochastic nucleation events in individual cells control the overall progression of polyQ aggregation in a living animal. The key finding that the biophysical principles associated with protein aggregation in small volumes remain the governing factors, even in the complex environment of a living organism, will be critical for the interpretation of in vivo data from a wide range of protein aggregation diseases.

scholarly journals Catechol-Containing Compounds are a Broad Class of Protein Aggregation Inhibitors: II. Rosmarinic Acid Potently Detoxifies Amylin Amyloid and Ameliorates Diabetic Pathology in HIP Rats

2020 ◽  
Author(s):  
Ling Wu ◽  
Paul Velander ◽  
Anne M. Brown ◽  
Yao Wang ◽  
Dongmin Liu ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Protein Aggregation ◽  
Rosmarinic Acid ◽  
Protein Misfolding ◽  
Broad Class ◽  
Diabetic Patients ◽  
Aggregation Inhibitors ◽  
Misfolding Diseases

AbstractProtein aggregation is associated with a large number of human protein misfolding diseases, yet FDA-approved drugs are currently not available. Amylin amyloid and plaque depositions in the pancreas are hallmark features of type 2 diabetes. Moreover, these amyloid deposits are implicated in the pathogenesis of diabetic complications such as neurodegeneration. We recently discovered that catechols and redox-related quinones/ anthraquinones represent a broad class of protein aggregation inhibitors. Further screening of a targeted library of natural compounds in complementary medicine that were enriched with catechol-containing compounds identified rosmarinic acid as a potent inhibitor of amylin aggregation (estimated inhibitory concentration IC50 = 200-300 nM). Structure-function relationship analysis of rosmarinic acid showed the additive effects of two catechol-containing components of the RA molecule. We further showed that RA does not reverse fibrillation back to monomeric amylin, but lead to non-toxic, remodeled protein aggregates. Rosmarinic acid has significant ex vivo efficacy in reducing human amylin oligomer levels in HIP rat sera as well as in sera from diabetic patients. In vivo efficacy studies of rosmarinic acid treatment with the diabetic HIP rat model demonstrated significant reduction in amyloid islet deposition and strong mitigation of diabetic pathology. Our work provides new in vitro molecular mechanisms and in vivo efficacy insights for a model nutraceutical agent against type 2 diabetes and other aging-related protein misfolding diseases.

Reliability of a Single β-Thromboglobulin Measurement in a Diabetic Population : Importance of PGE1 in Anticoagulant Mixture

1987 ◽  
Vol 57 (02) ◽  
pp. 201-204 ◽  
Author(s):  
P Y Scarabin ◽  
L Strain ◽  
C A Ludlam ◽  
J Jones ◽  
E M Kohner
Keyword(s):  
In Vitro Release ◽  
Mean Value ◽  
Reliable Estimate ◽  
Diabetic Patients ◽  
Single Measurement ◽  
Diabetic Population ◽  
The Difference ◽  
Vitro Release

SummaryDuring the collection of samples for plasma β-thromboglobulin (β-TG) determination, it is well established that artificially high values can be observed due to in-vitro release. To estimate the reliability of a single β-TG measurement, blood samples were collected simultaneously from both arms on two separate occasions in 56 diabetic patients selected for a clinical trial. From each arm, blood was taken into two tubes containing an anticoagulant mixture with (tube A) and without (tube B) PGE!. The overall mean value of B-TG in tube B was 1.14 times higher than in tube A (p <0.01). The markedly large between-arms variation accounted for the most part of within-subject variation in both tubes and was significantly greater in tube B than in tube A. Based on the difference between B-TG values from both arms, the number of subjects with artifically high B-TG values was significantly higher in tube B than in tube A on each occasion (overall rate: 28% and 14% respectively). Estimate of between-occasions variation showed that B-TG levels were relatively stable for each subject between two occasions in each tube. It is concluded that the use of PGEi decreases falsely high B-TG levels, but a single measurement of B-TG does not provide a reliable estimate of the true B-TG value in vivo.

scholarly journals A small molecule HIF-1α stabilizer that accelerates diabetic wound healing

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guodong Li ◽  
Chung-Nga Ko ◽  
Dan Li ◽  
Chao Yang ◽  
Wanhe Wang ◽  
...  
Keyword(s):  
Wound Healing ◽  
Small Molecule ◽  
Hypoxia Inducible Factor ◽  
Diabetic Patients ◽  
Diabetic Mice ◽  
Impaired Wound Healing ◽  
Von Hippel Lindau ◽  
Design And Synthesis

AbstractImpaired wound healing and ulcer complications are a leading cause of death in diabetic patients. In this study, we report the design and synthesis of a cyclometalated iridium(III) metal complex 1a as a stabilizer of hypoxia-inducible factor-1α (HIF-1α). In vitro biophysical and cellular analyses demonstrate that this compound binds to Von Hippel-Lindau (VHL) and inhibits the VHL–HIF-1α interaction. Furthermore, the compound accumulates HIF-1α levels in cellulo and activates HIF-1α mediated gene expression, including VEGF, GLUT1, and EPO. In in vivo mouse models, the compound significantly accelerates wound closure in both normal and diabetic mice, with a greater effect being observed in the diabetic group. We also demonstrate that HIF-1α driven genes related to wound healing (i.e. HSP-90, VEGFR-1, SDF-1, SCF, and Tie-2) are increased in the wound tissue of 1a-treated diabetic mice (including, db/db, HFD/STZ and STZ models). Our study demonstrates a small molecule stabilizer of HIF-1α as a promising therapeutic agent for wound healing, and, more importantly, validates the feasibility of treating diabetic wounds by blocking the VHL and HIF-1α interaction.

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