Biology subjects

Hutt, D. M.

Publications and source records attributed to Hutt, D. M..

4 recordsLinked to original sources

bioRxiv2019

Proteostasis and Energetics as Proteome Hallmarks of Aging and Influenza Challenge in Pulmonary Disease

Aging is associated with an increased risk for the development of many diseases. This is exemplified by the increased incidence of lung injury, muscle dysfunction and cognitive impairment in the elderly following influenza infection. Because the infectious cycle of flu is dependent upon the properties of the host, we examined the proteome of alveolar macrophages (AM) and type 2 cells (AT2) obtained from young (3 months) and old (18 months) naive mice and mice exposed to influenza A. Our proteomics data show that there is a maladaptive collapse of the proteostasis network (PN) and changes in mitochondrial pathways in the aged naive AM and AT2 proteomes. The mitochondrial imbalance and proteostatic collapse seen in aged cells places an excessive folding burden on these cells, which is further exacerbated following exposure to influenza A. Specifically, we see an imbalance in Hsp70 co-chaperones involved in protein folding and Hsp90 co-chaperones important for stress signaling pathways that are essential for cellular protection during aging. The acute challenge of influenza A infection of young and aged AM and AT2 cells reveals that age-associated changes in the chaperome affect the ability of these cells to properly manage the infection and post-infection biology, contributing to cytotoxicity. We posit that proteomic profiling of individual cell type specific responses provides a high impact approach to pinpoint fundamental molecular relationships that may contribute to the susceptibility to aging and environmental stress, providing a platform to identify new targets for therapeutic intervention to improve resiliency in the elderly.

cell biology↗

bioRxiv2019

Correction of Niemann-Pick type C1 disease with the histone deacetylase inhibitor valproic acid

Niemann-Pick type C (NPC) disease is primarily caused by mutations in the NPC1 gene and is characterized by the accumulation of unesterified cholesterol and lipids in the late endosomal (LE) and lysosomal (Ly) compartments. The most prevalent disease-linked mutation is the I1061T variant of NPC1, which exhibits defective folding and trafficking from the endoplasmic reticulum to the LE/Ly compartments. We now show that the FDA-approved histone deacetylase inhibitor (HDACi) valproic acid (VPA) corrects the folding and trafficking defect associated with I1061T-NPC1 leading to restoration of cholesterol homeostasis, an effect that is largely driven by a reduction in HDAC7 expression. The VPA-mediated trafficking correction is in part associated with an increase in the acetylation of lysine residues in the cysteine-rich domain of NPC1. The HDACi-mediated correction is synergistically improved by combining it with the FDA-approved anti-malarial, chloroquine, a known lysosomotropic compound, which improved the stability of the LE/Ly-localized fraction of the I1061T variant. We posit that combining the activity of VPA, to modulate epigentically the cellular acetylome, with chloroquine, to alter the lysosomal environment to favor stability of the trafficked I1061T variant protein, can have a significant therapeutic benefit in patients carrying at least one copy of the I1061T variant of NPC1, the most common disease-associated mutation leading to NPC disease. Given its ability to cross the blood brain barrier, we posit VPA provides a potential mechanism to improve the response to 2-hydroxypropyl-{beta}-cyclodextrin, by restoring functional NPC1 to cholesterol managing compartment as an adjunct therapy.

cell biology↗

bioRxiv2018

Managing the Spatial Covariance of Genetic Diversity in Niemann-Pick C1 Through Modulation of the Hsp70 Chaperone System

Genetic diversity provides a rich repository for understanding the role of proteostasis in the management of the protein fold to allow biology to evolve through variation in the population and in response to the environment. Failure in proteostasis can trigger multiple disease states affecting both human health and lifespan. Niemann-Pick C (NPC) disease is a genetic disorder mainly caused by mutations in NPC1, a multi-spanning transmembrane protein that is trafficked through the exocytic pathway to late endosomes and lysosomes (LE/Ly) to manage cholesterol homeostasis. Proteostatic defects triggered by >600 NPC1 variants found in the human population inhibit export of NPC1 protein from ER or function in downstream LE/Ly, leading to accumulation of cholesterol and rapid onset neurodegeneration in childhood for most patients. We now show that chemical allosteric inhibitors, such as JG98, targeting the cytosolic Hsp70 chaperone/co-chaperone complex improves the trafficking and stability of NPC1 variants with diverse NPC1 genotypes. By exploiting the knowledge-base of NPC1 variants found in the world-wide patient population using Variation Spatial Profiling (VSP), a Gaussian-process based machine learning (ML) approach, we show how the Hsp70 chaperone system alters the spatial covariance (SCV) tolerance of the ER and the SCV set-points for each residue of the NPC1 polypeptide chain differentially to improve trafficking efficiency and post-ER stability for variants distributed across the entire NPC1 polypeptide. The impact of JG98 is supported by the observation that silencing of Hsp70 specific nucleotide exchange factors (NEF) (BCL-anthogene (BAG) family) co-chaperones significantly improve the folding status of NPC1 variants. Together, these studies suggest that targeting the cytosolic Hsp70 system to adjust the SCV tolerance of the proteostasis network can improve recognition of the plasticity of the NPC1 fold found in the disease population for trafficking to the LE/Ly compartments.

genomics↗

bioRxiv2018

Management of Hsp90-Dependent Protein Folding by Small Molecule Targeting the Aha1 Co-Chaperone

The core cytosolic Hsp90 chaperone/co-chaperone complex plays a critical role in proteostasis management of human health and disease. To identify novel compounds that alter the ability of the Hsp90 co-chaperone Aha1 to modulate the ATPase activity found in multiple folding diseases ranging from steroid hormone receptor (SHR) sensitive prostate cancer to tauopathies associated with neurodegenerative diseases, we employed a high throughput screening (HTS) assay to monitor selectively Aha1-stimulated Hsp90 (ASH) ATPase activity. The ASH assay identified SEW04784 (SEW), a small molecule that disrupts ASH activity without inhibiting the basal Hsp90 ATPase activity. NMR analysis reveals that SEW binds to the C-terminal domain of Aha1 to disrupt its asymmetric binding to Hsp90 leading to abrogation of its chaperoning activity of Hsp90. SEW exhibits therapeutic potential by blocking the transcriptional activity of prostate cancer (PCa) associated variants of the androgen receptor (AR) in a cell-based model of PCa. Additionally, SEW exhibits the ability to clear toxic, phosphorylated tau aggregated species associated with tauopathies. By not directly impacting the basal ATPase function of the abundant and ubiquitous Hsp90, SEW could provide a therapeutic approach for mitigation of client-specific proteostatic disease.

biochemistry↗