scholarly journals MG132 induces progerin clearance and improves disease phenotypes in fibroblasts of patients affected with Hutchinson-Gilford Progeria-like syndromes

2021 ◽  
Author(s):  
Karim HARHOURI ◽  
Pierre CAU ◽  
Franck CASEY ◽  
Koffi Mawuse GUEDENON ◽  
Yassamine DOUBAJ ◽  
...  
Keyword(s):  
De Novo ◽  
Accelerated Aging ◽  
Therapeutic Trial ◽  
Cell Nuclei ◽  
Gene Encoding ◽  
Prelamin A ◽  
Exon 11 ◽  
Cellular Phenotypes ◽  
Carboxy Terminal ◽  
Hutchinson Gilford Progeria Syndrome

Progeroid Syndromes (PS), including Hutchinson-Gilford Progeria Syndrome (HGPS, OMIM #176670), are premature and accelerated aging that clinically resemble some aspects of advancing physiological aging. Most classical HGPS patients carry a de novo point mutation within exon 11 of the LMNA gene encoding A-type Lamins. This mutation activates a cryptic splice site leading to the deletion of 50 amino acids at its carboxy-terminal domain, resulting in a truncated and permanently farnesylated Prelamin A called Prelamin A Δ50 or Progerin that accumulates in HGPS cell nuclei and is a hallmark of the disease. Some patients with PS carry other LMNA mutations affecting exon 11 splicing, leading to defects in nuclear A-type Lamins and are named “HGPS-like” patients. They also produce Progerin and/or other truncated Prelamin A isoforms (Δ35 and & Δ90). We recently found that MG132, a proteasome inhibitor, induced progerin clearance in classical HGPS through autophagy activation and splicing regulation. Here, we show that MG132 induces aberrant prelamin A clearance and improves cellular phenotypes in HGPS-like patient cells. These results provide preclinical proof of principle for the use of a promising class of molecules toward a potential therapy for children with HGPS-like, who may therefore be eligible for inclusion in a therapeutic trial based on this approach, together with classical HGPS patients.

scholarly journals Baricitinib, a JAK-STAT Inhibitor, Reduces the Cellular Toxicity of the Farnesyltransferase Inhibitor Lonafarnib in Progeria Cells

2021 ◽  
Vol 22 (14) ◽  
pp. 7474
Author(s):  
Rouven Arnold ◽  
Elena Vehns ◽  
Hannah Randl ◽  
Karima Djabali
Keyword(s):  
De Novo ◽  
Early Death ◽  
Premature Aging ◽  
Farnesyltransferase Inhibitor ◽  
Cellular Toxicity ◽  
Signaling Axis ◽  
Cellular Stresses ◽  
Exon 11 ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome

Hutchinson–Gilford progeria syndrome (HGPS) is an ultra-rare multisystem premature aging disorder that leads to early death (mean age of 14.7 years) due to myocardial infarction or stroke. Most cases have a de novo point mutation at position G608G within exon 11 of the LMNA gene. This mutation leads to the production of a permanently farnesylated truncated prelamin A protein called “progerin” that is toxic to the cells. Recently, farnesyltransferase inhibitor (FTI) lonafarnib has been approved by the FDA for the treatment of patients with HGPS. While lonafarnib treatment irrefutably ameliorates HGPS disease, it is however not a cure. FTI has been shown to cause several cellular side effects, including genomic instability as well as binucleated and donut-shaped nuclei. We report that, in addition to these cellular stresses, FTI caused an increased frequency of cytosolic DNA fragment formation. These extranuclear DNA fragments colocalized with cGAs and activated the cGAS-STING-STAT1 signaling axis, upregulating the expression of proinflammatory cytokines in FTI-treated human HGPS fibroblasts. Treatment with lonafarnib and baricitinib, a JAK-STAT inhibitor, not only prevented the activation of the cGAS STING-STAT1 pathway, but also improved the overall HGPS cellular homeostasis. These ameliorations included progerin levels, nuclear shape, proteostasis, cellular ATP, proliferation, and the reduction of cellular inflammation and senescence. Thus, we suggest that combining lonafarnib with baricitinib might provide an opportunity to reduce FTI cellular toxicity and ameliorate HGPS symptoms further than lonafarnib alone.

Abstract 13652: An Innate YAP/TAZ Mechanosensing Deficit in Hutchinson-Gilford Progeria Syndrome

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Brandon K Walther ◽  
Anahita Mojiri ◽  
Navaneeth Krishna Rajeeva Pandian ◽  
Jacques Ohayon ◽  
Huie Wang ◽  
...  
Keyword(s):  
Shear Stress ◽  
Accelerated Aging ◽  
Scaffolding Protein ◽  
Therapeutic Approaches ◽  
Gene Encoding ◽  
New Therapeutic Approaches ◽  
Age Related ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome ◽  
Mechanical Aging

Hutchinson-Gilford Progeria Syndrome (HGPS) is a disease of accelerated aging causing death in the mid-teens from myocardial infarction or stroke. The disease is caused by a point mutation in the gene encoding lamin-A. The mutated scaffolding protein is aberrantly farnesylated inducing a constellation of defects included nuclear abnormalities, genomic damage, and rapid senescence. Therapy targeting the abnormal farnesylation provides a modest extension of life, thus new insights and therapeutic approaches are urgently needed for these children. Consistent with previous morphological observations and new studies implicating YAP/TAZ mechanobiology as an important mechanical pathway for endothelial cell (EC) health under shear stress, we hypothesized that HGPS ECs have an innate mechanical disturbance rendering them unable to respond to external, atheroprotective cues. We used a microfluidic vessel-on-a-chip with channel geometries and fluid flow to precisely model the hemodynamic stimuli present in vasculature as we have previously described. We cultured iPSC-derived HGPS ECs in this system to study mechanoresponse to shear stress and YAP/TAZ signaling. HGPS ECs manifest a rounded, flattened appearance characteristic of senescent ECs, are unable to align in response to flow, and have aberrant YAP/TAZ activity despite unidirectional laminar flow. To explore the physical underpinnings of such biochemical disturbances, we used atomic force microscopy (AFM) to precisely characterize the shape of individual HGPS cells, and their deformation to a controlled force applied by the AFM cantilever. Preliminary measurements confirmed that HGPS cells have a reduced profile and are compositely stiffer (nuclear modulus + cytoskeletal modulus) than cells derived from the unaffected parent of the child. These data provide evidence of altered biophysical properties of senescent cells which we term “mechanical aging,” which is associated with aberrant signaling in response to hemodynamic stimuli. Further characterization of mechanical aging may lead to new therapeutic approaches for HGPS and other age-related diseases.

scholarly journals Imbalanced nucleocytoskeletal connections create common polarity defects in progeria and physiological aging

2019 ◽  
Vol 116 (9) ◽  
pp. 3578-3583 ◽  
Author(s):  
Wakam Chang ◽  
Yuexia Wang ◽  
G. W. Gant Luxton ◽  
Cecilia Östlund ◽  
Howard J. Worman ◽  
...  
Keyword(s):  
Accelerated Aging ◽  
Nuclear Movement ◽  
Prelamin A ◽  
Physiological Aging ◽  
3T3 Fibroblasts ◽  
Normal Individuals ◽  
Actin Cables ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome ◽  
Nih 3T3

Studies of the accelerated aging disorder Hutchinson–Gilford progeria syndrome (HGPS) can potentially reveal cellular defects associated with physiological aging. HGPS results from expression and abnormal nuclear envelope association of a farnesylated, truncated variant of prelamin A called “progerin.” We surveyed the diffusional mobilities of nuclear membrane proteins to identify proximal effects of progerin expression. The mobilities of three proteins—SUN2, nesprin-2G, and emerin—were reduced in fibroblasts from children with HGPS compared with those in normal fibroblasts. These proteins function together in nuclear movement and centrosome orientation in fibroblasts polarizing for migration. Both processes were impaired in fibroblasts from children with HGPS and in NIH 3T3 fibroblasts expressing progerin, but were restored by inhibiting protein farnesylation. Progerin affected both the coupling of the nucleus to actin cables and the oriented flow of the cables necessary for nuclear movement and centrosome orientation. Progerin overexpression increased levels of SUN1, which couples the nucleus to microtubules through nesprin-2G and dynein, and microtubule association with the nucleus. Reducing microtubule-nuclear connections through SUN1 depletion or dynein inhibition rescued the polarity defects. Nuclear movement and centrosome orientation were also defective in fibroblasts from normal individuals over 60 y, and both defects were rescued by reducing the increased level of SUN1 in these cells or inhibiting dynein. Our results identify imbalanced nuclear engagement of the cytoskeleton (microtubules: high; actin filaments: low) as the basis for intrinsic cell polarity defects in HGPS and physiological aging and suggest that rebalancing the connections can ameliorate the defects.

scholarly journals ESCRT-III controls nuclear envelope deformation induced by progerin

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jun Arii ◽  
Fumio Maeda ◽  
Yuhei Maruzuru ◽  
Naoto Koyanagi ◽  
Akihisa Kato ◽  
...  
Keyword(s):  
Nuclear Membrane ◽  
Protein Complex ◽  
Premature Aging ◽  
Bafilomycin A1 ◽  
Gene Encoding ◽  
Truncated Protein ◽  
Cytoplasmic Membranes ◽  
Cellular Phenotypes ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome

Abstract Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disorder, caused by mutation in the gene encoding lamin A/C, which produces a truncated protein called progerin. In cells from HGPS patients, progerin accumulates at the nuclear membrane (NM), where it causes NM deformations. In this study, we investigated whether progerin-induced NM deformation involved ESCRT-III, a protein complex that remodels nuclear and cytoplasmic membranes. The ESCRT-III protein CHMP4B was recruited to sites of aberrant NM proliferation in human cells ectopically expressing progerin and in patient-derived HGPS fibroblasts. Derepression of NM deformation in these cells was observed following depletion of CHMP4B or an ESCRT-III adaptor, ALIX. Treatment with rapamycin (which induce autophagic clearance of progerin and reverse progerin-induced cellular phenotypes) down-regulated progerin-induced NM deformation, whereas treatment with bafilomycin A1 (an inhibitor of autophagy and lysosome-based degradation) or CHMP4B depletion antagonized the effects of rapamycin. These results indicate that the ALIX-mediated ESCRT-III pathway plays a suppressive role in progerin-induced NM deformation and suggest that autophagy down-regulates progerin-induced NM deformation in a manner dependent on ESCRT-III machinery.

scholarly journals Gain-of-function GABRB3 variants identified in vigabatrin-hypersensitive epileptic encephalopathies

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Nathan L Absalom ◽  
Vivian W Y Liao ◽  
Kavitha Kothur ◽  
Dinesh C Indurthi ◽  
Bruce Bennetts ◽  
...  
Keyword(s):  
De Novo ◽  
Drug Effects ◽  
Receptor Expression ◽  
Aminobutyric Acid ◽  
Loss Of Function ◽  
Molecular Phenotype ◽  
Gain Of Function ◽  
Gene Encoding ◽  
Epileptic Encephalopathies ◽  
Receptor Phenotype

Abstract Variants in the GABRB3 gene encoding the β3-subunit of the γ-aminobutyric acid type A ( receptor are associated with various developmental and epileptic encephalopathies. Typically, these variants cause a loss-of-function molecular phenotype whereby γ-aminobutyric acid has reduced inhibitory effectiveness leading to seizures. Drugs that potentiate inhibitory GABAergic activity, such as nitrazepam, phenobarbital or vigabatrin, are expected to compensate for this and thereby reduce seizure frequency. However, vigabatrin, a drug that inhibits γ-aminobutyric acid transaminase to increase tonic γ-aminobutyric acid currents, has mixed success in treating seizures in patients with GABRB3 variants: some patients experience seizure cessation, but there is hypersensitivity in some patients associated with hypotonia, sedation and respiratory suppression. A GABRB3 variant that responds well to vigabatrin involves a truncation variant (p.Arg194*) resulting in a clear loss-of-function. We hypothesized that patients with a hypersensitive response to vigabatrin may exhibit a different γ-aminobutyric acid A receptor phenotype. To test this hypothesis, we evaluated the phenotype of de novo variants in GABRB3 (p.Glu77Lys and p.Thr287Ile) associated with patients who are clinically hypersensitive to vigabatrin. We introduced the GABRB3 p.Glu77Lys and p.Thr287Ile variants into a concatenated synaptic and extrasynaptic γ-aminobutyric acid A receptor construct, to resemble the γ-aminobutyric acid A receptor expression by a patient heterozygous for the GABRB3 variant. The mRNA of these constructs was injected into Xenopus oocytes and activation properties of each receptor measured by two-electrode voltage clamp electrophysiology. Results showed an atypical gain-of-function molecular phenotype in the GABRB3 p.Glu77Lys and p.Thr287Ile variants characterized by increased potency of γ-aminobutyric acid A without change to the estimated maximum open channel probability, deactivation kinetics or absolute currents. Modelling of the activation properties of the receptors indicated that either variant caused increased chloride flux in response to low concentrations of γ-aminobutyric acid that mediate tonic currents. We therefore propose that the hypersensitivity reaction to vigabatrin is a result of GABRB3 variants that exacerbate GABAergic tonic currents and caution is required when prescribing vigabatrin. In contrast, drug strategies increasing tonic currents in loss-of-function variants are likely to be a safe and effective therapy. This study demonstrates that functional genomics can explain beneficial and adverse anti-epileptic drug effects, and propose that vigabatrin should be considered in patients with clear loss-of-function GABRB3 variants.

scholarly journals High-Throughput Screen Detects Calcium Signaling Dysfunction in Hutchinson-Gilford Progeria Syndrome

2021 ◽  
Vol 22 (14) ◽  
pp. 7327
Author(s):  
Juan A. Fafián-Labora ◽  
Miriam Morente-López ◽  
Fco. Javier de Toro ◽  
María C. Arufe
Keyword(s):  
Calcium Signaling ◽  
Rare Disease ◽  
Cell Lines ◽  
Healthy Aging ◽  
Accelerated Aging ◽  
Cytosolic Calcium ◽  
Calcium Handling ◽  
Therapeutic Window ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome

Hutchinson–Gilford progeria syndrome (HGPS) is a deadly childhood disorder, which is considered a very rare disease. It is caused by an autosomal dominant mutation on the LMNA gene, and it is characterized by accelerated aging. Human cell lines from HGPS patients and healthy parental controls were studied in parallel using next-generation sequencing (NGS) to unravel new non-previously altered molecular pathways. Nine hundred and eleven transcripts were differentially expressed when comparing healthy versus HGPS cell lines from a total of 21,872 transcripts; ITPR1, ITPR3, CACNA2D1, and CAMK2N1 stood out among them due to their links with calcium signaling, and these were validated by Western blot analysis. It was observed that the basal concentration of intracellular Ca2+ was statistically higher in HGPS cell lines compared to healthy ones. The relationship between genes involved in Ca2+ signaling and mitochondria-associated membranes (MAM) was demonstrated through cytosolic calcium handling by means of an automated fluorescent plate reading system (FlexStation 3, Molecular Devices), and apoptosis and mitochondrial ROS production were examined by means of flow cytometry analysis. Altogether, our data suggest that the Ca2+ signaling pathway is altered in HGPS at least in part due to the overproduction of reactive oxygen species (ROS). Our results unravel a new therapeutic window for the treatment of this rare disease and open new strategies to study pathologies involving both accelerated and healthy aging.

Cortical Thinning Associated with Age and CSF Biomarkers in Early Parkinson’s Disease Is Modified by the SNCA rs356181 Polymorphism

2018 ◽  
Vol 18 (5-6) ◽  
pp. 233-238
Author(s):  
Frederic Sampedro ◽  
Juan Marín-Lahoz ◽  
Saul Martínez-Horta ◽  
Javier Pagonabarraga ◽  
Jaime Kulisevsky
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Cognitive Decline ◽  
De Novo ◽  
Brain Regions ◽  
Cortical Atrophy ◽  
Csf Biomarkers ◽  
Gene Encoding ◽  
Cortical Thinning ◽  
Age Related

The role of cerebrospinal fluid (CSF) biomarkers such as CSF α-synuclein and CSF tau in predicting cognitive decline in Parkinson’s disease (PD) continues to be inconsistent. Here, using a cohort of de novo PD patients with preserved cognition from the Parkinson’s Progression Markers Initiative (PPMI), we show that the SNCA rs356181 single nucleotide polymorphism (SNP) modulates the effect of these CSF biomarkers on cortical thinning. Depending on this SNP’s genotype, cortical atrophy was associated with either higher or lower CSF biomarker levels. Additionally, this SNP modified age-related atrophy. Importantly, the integrity of the brain regions where this phenomenon was observed correlated with cognitive measures. These results suggest that this genetic variation of the gene encoding the α-synuclein protein, known to be involved in the development of PD, also interferes in its subsequent neurodegeneration. Overall, our findings could shed light on the so far incongruent association of common CSF biomarkers with cognitive decline in PD.

scholarly journals Activating the synthesis of progerin, the mutant prelamin A in Hutchinson–Gilford progeria syndrome, with antisense oligonucleotides

2009 ◽  
Vol 18 (13) ◽  
pp. 2462-2471 ◽  
Author(s):  
Loren G. Fong ◽  
Timothy A. Vickers ◽  
Emily A. Farber ◽  
Christine Choi ◽  
Ui Jeong Yun ◽  
...  
Keyword(s):  
Antisense Oligonucleotides ◽  
Prelamin A ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome

scholarly journals Regulation of the Bacillus subtilis bcrC Bacitracin Resistance Gene by Two Extracytoplasmic Function σ Factors

2002 ◽  
Vol 184 (22) ◽  
pp. 6123-6129 ◽  
Author(s):  
Min Cao ◽  
John D. Helmann
Keyword(s):  
Bacillus Subtilis ◽  
Resistance Gene ◽  
Mutant Strain ◽  
Stress Responses ◽  
Double Mutant ◽  
De Novo ◽  
De Novo Synthesis ◽  
Gene Encoding ◽  
Single Promoter ◽  
Higher Sensitivity

ABSTRACT Bacitracin resistance is normally conferred by either of two major mechanisms, the BcrABC transporter, which pumps out bacitracin, or BacA, an undecaprenol kinase that provides C55-isoprenyl phosphate by de novo synthesis. We demonstrate that the Bacillus subtilis bcrC (ywoA) gene, encoding a putative bacitracin transport permease, is an important bacitracin resistance determinant. A bcrC mutant strain had an eightfold-higher sensitivity to bacitracin. Expression of bcrC initiated from a single promoter site that could be recognized by either of two extracytoplasmic function (ECF) σ factors, σX or σM. Bacitracin induced expression of bcrC, and this induction was dependent on σM but not on σX. Under inducing conditions, expression was primarily dependent on σM. As a consequence, a sigM mutant was fourfold more sensitive to bacitracin, while the sigX mutant was only slightly sensitive. A sigX sigM double mutant was similar to a bcrC mutant in sensitivity. These results support the suggestion that one function of B. subtilis ECF σ factors is to coordinate antibiotic stress responses.

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