Biology subjects

Jackrel, M. E.

Publications and source records attributed to Jackrel, M. E..

5 recordsLinked to original sources

bioRxiv2025

Substituent-based Modulation of Self-Assembly and Immunogenicity of Amphipathic Peptides

Peptide-based biomaterials assembled through monomer-by-monomer self-assembly provide versatile platforms for biomedical applications due to their adjustable physicochemical properties, biocompatibility, and dynamic nature. The self-assembly process largely depends on primary sequence features, such as hydrophobicity, length, and charge, which influence the formation of various nanostructures, including fibrils and hydrogels. Amphipathic peptides, characterized by alternating polar and hydrophobic residues, are especially effective in forming supramolecular nanofibers stabilized by {pi}-{pi} interactions and hydrogen bonds. Chemical modifications, particularly on aromatic side chains, have proven to be a promising approach for controlling assembly morphology, stability, and biological activity. In organic chemistry, the use of chemical substituents, such as halogens, alkyl groups, or electron-donating and electron-withdrawing groups, has been widely employed to alter reactivity, stability, and molecular interactions for diverse applications, including catalysts, pharmaceuticals, and materials science. However, the influence of these substituents on peptide packing and in vivo immunogenicity remains relatively unexplored. In this study, we systematically examine how changes in the position and nature of substituents on benzyl groups attached to short amphipathic peptides affect self-assembly, fibril morphology, and immune responses. By introducing different electron-donating and withdrawing groups at the para-position of benzyl rings and modifying the chain length connecting the backbone to the aromatic moiety, we observe notable effects on fibril formation, molecular packing, and immunogenicity both in vitro and in vivo. Our results show that subtle chemical modifications are effective tools for designing tailored peptide nanomaterials with promising potential in vaccine delivery, tissue engineering, and regenerative medicine.

bioengineering↗

bioRxiv2024

Enantiomeric histidine-rich peptide coacervates enhance antigen delivery to T cells

Peptides and peptidomimetics that self-assemble via LLPS have recently emerged as building blocks for fabricating functional biomaterials due to their unique physicochemical properties and dynamic nature. One of lifes most distinctive signatures is its selectivity for chiral molecules and, to date, coacervates comprised of D-amino acids have not been reported. Here, we demonstrate that histidine-rich repeats of (GHGXY)4 (X=L/V/P) and their enantiomers undergo LLPS opening new avenues for enhancing coacervate stability. Through a series of biophysical studies, we find that LLPS kinetics, droplet size, fusion, and encapsulation efficiency are dictated by the primary sequence. Further, these coacervates can encapsulate therapeutic cargo which are then internalized via endocytic mechanisms. Finally, we show that the coacervates enhance antigen presentation to CD4+ and CD8+ T cells resulting in robust proliferation and production of functional cytokines. Collectively, our study describes the development and characterization of enantiomeric peptide coacervates as attractive vaccine delivery vehicles with tunable physicochemical properties. HIGHLIGHTSO_LID amino acid-peptides were used for the first time to construct phase separating coacervates C_LIO_LIChirality does not restrict LLPS or modulate other coacervate properties C_LIO_LIAntigen delivery using chiral coacervates enhances and prolongs presentation to T cells C_LI PROGRESS AND POTENTIALPeptides can undergo self-assembly via liquid-liquid phase separation (LLPS) to result in solute-rich coacervates that can serve as biomaterials. Using histidine-rich peptide repeats, this work demonstrates that peptides composed of entirely D-amino acids can form functional coaceravtes. The kinetics of LLPS and bulk properties of the droplets can be controlled through simple amino acid substitutions. The coacervates, while immunologically inert, exert an adjuvanting effect and enhance antigen presentation to T cells leading to proliferation and functional cytokine production. The materials showcased here possess high translational potential for combined delivery of immunomodulators and antigens for vaccine delivery against infectious diseases or cancer. The deliverables from this study will also inspire the development of chiral systems that will contribute to the knowledge of cellular processes associated with phase changes integral to both physiology and pathology.

bioengineering↗

bioRxiv2024

Seeding competent TDP-43 persists in human patient and mouse muscle

TAR DNA-binding protein 43 (TDP-43) is an RNA binding protein that accumulates as aggregates in the central nervous system of some neurodegenerative diseases. However, TDP-43 aggregation is also a sensitive and specific pathologic feature found in a family of degenerative muscle diseases termed inclusion body myopathy (IBM). TDP-43 aggregates from ALS and FTD brain lysates may serve as self-templating aggregate seeds in vitro and in vivo, supporting a prion-like spread from cell to cell. Whether a similar process occurs in IBM patient muscle is not clear. We developed a mouse model of inducible, muscle-specific cytoplasmic localized TDP-43. These mice develop muscle weakness with robust accumulation of insoluble and phosphorylated sarcoplasmic TDP-43, leading to eosinophilic inclusions, altered proteostasis and changes in TDP-43-related RNA processing that resolve with the removal of doxycycline. Skeletal muscle lysates from these mice also have seeding competent TDP-43, as determined by a FRET-based biosensor, that persists for weeks upon resolution of TDP-43 aggregate pathology. Human muscle biopsies with TDP-43 pathology also contain TDP-43 aggregate seeds. Using lysates from muscle biopsies of patients with IBM, IMNM and ALS we found that TDP-43 seeding capacity was specific to IBM. Surprisingly, TDP-43 seeding capacity anti-correlated with TDP-43 aggregate and vacuole abundance. These data support that TDP-43 aggregate seeds are present in IBM skeletal muscle and represent a unique TDP-43 pathogenic species not previously appreciated in human muscle disease. SummaryTDP-43 aggregate seeds persist in mouse and human skeletal muscle independent of large TDP-43 inclusions.

pathology↗

bioRxiv2023

MANF stimulates autophagy and restores mitochondrial homeostasis to treat toxic proteinopathy

Misfolded protein aggregates may cause toxic proteinopathy, including autosomal dominant tubulointerstitial kidney disease due to uromodulin mutations (ADTKD-UMOD), one of the leading hereditary kidney diseases, and Alzheimers disease etc. There are no targeted therapies. ADTKD is also a genetic form of renal fibrosis and chronic kidney disease, which affects 500 million people worldwide. For the first time, in our newly generated mouse model recapitulating human ADTKD-UMOD carrying a leading UMOD deletion mutation, we show that autophagy/mitophagy and mitochondrial biogenesis are severely impaired, leading to cGAS- STING activation and tubular injury. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is a novel endoplasmic reticulum stress-regulated secreted protein. We provide the first study that inducible tubular overexpression of MANF after the onset of disease stimulates autophagy/mitophagy and clearance of the misfolded UMOD, and promotes mitochondrial biogenesis through p-AMPK enhancement, resulting in protection of kidney function. Conversely, genetic ablation of endogenous MANF upregulated in the mutant mouse and human tubular cells worsens autophagy suppression and kidney fibrosis. Together, we discover MANF as a novel biotherapeutic protein and elucidate previously unknown mechanisms of MANF in regulating organelle homeostasis to treat ADTKD, which may have broad therapeutic application to treat various proteinopathies.

cell biology↗

bioRxiv2020

Tuning Hsp104 specificity to selectively detoxify alpha-synuclein

Hsp104 is an AAA+ protein disaggregase that solubilizes and reactivates proteins trapped in aggregated states. We have engineered potentiated Hsp104 variants to mitigate toxic misfolding of -synuclein, TDP-43, and FUS implicated in fatal neurodegenerative disorders. Though potent disaggregases, these enhanced Hsp104 variants lack substrate specificity, and can have unfavorable off-target effects. Here, to lessen off-target effects, we engineer substrate-specific Hsp104 variants. By altering Hsp104 pore loops that engage substrate, we disambiguate Hsp104 variants that selectively suppress -synuclein toxicity but not TDP-43 or FUS toxicity. Remarkably, -synuclein-specific Hsp104 variants emerge that mitigate -synuclein toxicity via distinct ATPase-dependent mechanisms, involving -synuclein disaggregation or detoxification of -synuclein conformers without disaggregation. Importantly, both types of -synuclein-specific Hsp104 variant reduce dopaminergic neurodegeneration in a C. elegans model of Parkinsons disease more effectively than non-specific variants. We suggest that increasing the substrate specificity of enhanced disaggregases could be applied broadly to tailor therapeutics for neurodegenerative disease.

bioengineering↗