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Hwang S, Balana AT, Martin B, Clarkson M, Di Lello P, Wu H, Li Y, Fuhrmann J, Dagdas Y, Holder P, Schroeder CI, Miller SE, Gao X. Bioproduction Platform to Generate Functionalized Disulfide-Constrained Peptide Analogues. ACS BIO & MED CHEM AU 2024; 4:190-203. [PMID: 39184057 PMCID: PMC11342346 DOI: 10.1021/acsbiomedchemau.4c00026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 07/02/2024] [Accepted: 07/03/2024] [Indexed: 08/27/2024]
Abstract
Disulfide-constrained peptides (DCPs) have gained increased attention as a drug modality due to their exceptional stability and combined advantages of large biologics and small molecules. Chemical synthesis, although widely used to produce DCPs, is associated with high cost, both economically and environmentally. To reduce the dependence on solid phase peptide synthesis and the negative environmental footprint associated with it, we present a highly versatile, low-cost, and environmentally friendly bioproduction platform to generate DCPs and their conjugates as well as chemically modified or isotope-labeled DCPs. Using the DCP against the E3 ubiquitin ligase Zinc and Ring Finger 3, MK1-3.6.10, as a model peptide, we have demonstrated the use of bacterial expression, combined with Ser ligation or transglutaminase-mediated XTEN ligation, to produce multivalent MK1-3.6.10 and MK1-3.6.10 with N-terminal functional groups. We have also developed a bioproduction method for the site-specific incorporation of unnatural amino acids into recombinant DCPs by the amber codon suppression system. Lastly, we produced 15N/13C-labeled MK1-3.6.10 with high yield and assessed the performance of a semiautomated resonance assignment workflow that could be used to accelerate binding studies and structural characterization of DCPs. This study provides a proof of concept to generate functionalized DCPs using bioproduction, providing a potential solution to alleviate the reliance on hazardous chemicals, reduce the cost, and expedite the timeline for DCP discovery.
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Kschonsak YT, Gao X, Miller SE, Hwang S, Marei H, Wu P, Li Y, Ruiz K, Dorighi K, Holokai L, Perampalam P, Tsai WTK, Kee YS, Agard NJ, Harris SF, Hannoush RN, de Sousa E Melo F. Potent and selective binders of the E3 ubiquitin ligase ZNRF3 stimulate Wnt signaling and intestinal organoid growth. Cell Chem Biol 2024; 31:1176-1187.e10. [PMID: 38056465 DOI: 10.1016/j.chembiol.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 08/21/2023] [Accepted: 11/10/2023] [Indexed: 12/08/2023]
Abstract
Selective and precise activation of signaling transduction cascades is key for cellular reprogramming and tissue regeneration. However, the development of small- or large-molecule agonists for many signaling pathways has remained elusive and is rate limiting to realize the full clinical potential of regenerative medicine. Focusing on the Wnt pathway, here we describe a series of disulfide-constrained peptides (DCPs) that promote Wnt signaling activity by modulating the cell surface levels of ZNRF3, an E3 ubiquitin ligase that controls the abundance of the Wnt receptor complex FZD/LRP at the plasma membrane. Mechanistically, monomeric DCPs induce ZNRF3 ubiquitination, leading to its cell surface clearance, ultimately resulting in FZD stabilization. Furthermore, we engineered multimeric DCPs that induce expansive growth of human intestinal organoids, revealing a dependence between valency and ZNRF3 clearance. Our work highlights a strategy for the development of potent, biologically active Wnt signaling pathway agonists via targeting of ZNRF3.
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Thakur AK, Miller SE, Liau NPD, Hwang S, Hansen S, de Sousa E Melo F, Sudhamsu J, Hannoush RN. Synthetic Multivalent Disulfide-Constrained Peptide Agonists Potentiate Wnt1/β-Catenin Signaling via LRP6 Coreceptor Clustering. ACS Chem Biol 2023; 18:772-784. [PMID: 36893429 DOI: 10.1021/acschembio.2c00753] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Wnt ligands are critical for tissue homeostasis and form a complex with LRP6 and frizzled coreceptors to initiate Wnt/β-catenin signaling. Yet, how different Wnts achieve various levels of signaling activation through distinct domains on LRP6 remains elusive. Developing tool ligands that target individual LRP6 domains could help elucidate the mechanism of Wnt signaling regulation and uncover pharmacological approaches for pathway modulation. We employed directed evolution of a disulfide constrained peptide (DCP) to identify molecules that bind to the third β-propeller domain of LRP6. The DCPs antagonize Wnt3a while sparing Wnt1 signaling. Using PEG linkers with different geometries, we converted the Wnt3a antagonist DCPs to multivalent molecules that potentiated Wnt1 signaling by clustering the LRP6 coreceptor. The mechanism of potentiation is unique as it occurred only in the presence of extracellular secreted Wnt1 ligand. While all DCPs recognized a similar binding interface on LRP6, they displayed different spatial orientations that influenced their cellular activities. Moreover, structural analyses revealed that the DCPs exhibited new folds that were distinct from the parent DCP framework they were evolved from. The multivalent ligand design principles highlighted in this study provide a path for developing peptide agonists that modulate different branches of cellular Wnt signaling.
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Awotoye W, Comnick C, Pendleton C, Zeng E, Alade A, Mossey PA, Gowans LJJ, Eshete MA, Adeyemo WL, Naicker T, Adeleke C, Busch T, Li M, Petrin A, Olotu J, Hassan M, Pape J, Miller SE, Donkor P, Anand D, Lachke SA, Marazita ML, Adeyemo AA, Murray JC, Albokhari D, Sobreira N, Butali A. Genome-wide Gene-by-Sex Interaction Studies Identify Novel Nonsyndromic Orofacial Clefts Risk Locus. J Dent Res 2021; 101:465-472. [PMID: 34689653 DOI: 10.1177/00220345211046614] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Risk loci identified through genome-wide association studies have explained about 25% of the phenotypic variations in nonsyndromic orofacial clefts (nsOFCs) on the liability scale. Despite the notable sex differences in the incidences of the different cleft types, investigation of loci for sex-specific effects has been understudied. To explore the sex-specific effects in genetic etiology of nsOFCs, we conducted a genome-wide gene × sex (GxSex) interaction study in a sub-Saharan African orofacial cleft cohort. The sample included 1,019 nonsyndromic orofacial cleft cases (814 cleft lip with or without cleft palate and 205 cleft palate only) and 2,159 controls recruited from 3 sites (Ethiopia, Ghana, and Nigeria). An additive logistic model was used to examine the joint effects of the genotype and GxSex interaction. Furthermore, we examined loci with suggestive significance (P < 1E-5) in the additive model for the effect of the GxSex interaction only. We identified a novel risk locus on chromosome 8p22 with genome-wide significant joint and GxSex interaction effects (rs2720555, p2df = 1.16E-08, pGxSex = 1.49E-09, odds ratio [OR] = 0.44, 95% CI = 0.34 to 0.57). For males, the risk of cleft lip with or without cleft palate at this locus decreases with additional copies of the minor allele (p < 0.0001, OR = 0.60, 95% CI = 0.48 to 0.74), but the effect is reversed for females (p = 0.0004, OR = 1.36, 95% CI = 1.15 to 1.60). We replicated the female-specific effect of this locus in an independent cohort (p = 0.037, OR = 1.30, 95% CI = 1.02 to 1.65), but no significant effect was found for the males (p = 0.29, OR = 0.86, 95% CI = 0.65 to 1.14). This locus is in topologically associating domain with craniofacially expressed and enriched genes during embryonic development. Rare coding mutations of some of these genes were identified in nsOFC cohorts through whole exome sequencing analysis. Our study is additional proof that genome-wide GxSex interaction analysis provides an opportunity for novel findings of loci and genes that contribute to the risk of nsOFCs.
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Vergales BD, Murray PD, Miller SE, Vergales JE. Safety and efficacy of a home nasogastric monitoring program for premature infants. J Neonatal Perinatal Med 2021; 15:165-170. [PMID: 34459419 DOI: 10.3233/npm-210790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND A novel home monitoring program, in which premature infants are cared for at home with a nasogastric tube in place prior to achievement of full oral feeding, was evaluated. The program combines a digital, fully EMR-integrated, virtual daily rounding platform with direct provider video and telephone contact. METHODS A case-control study was performed evaluating infants < 34 weeks' gestation who were followed in our program. A historical control group, was created by matching 2 : 1 based on gestational age±6 days, retroactively. RESULT 15 patients discharged in the program were compared with 30 controls. The home cohort gained an average of 30 g/day compared with the in-hospital group at 27g/day (p = 0.325). The home group required a mean of 5.9±2.9 days to full oral feeding once discharged, not different from the control group at 5.4±3.7 days (p = 0.606). The percentage of oral feeds for the home cohort, however, increased at a rate of 12.2%before discharge compared to rising 57%at home (p < 0.001). The control group spent an additional 8.1±3.9 days in the hospital after reaching criteria. There were no reported adverse events or readmissions. CONCLUSION Premature infants can safely advance oral feeds using a home monitoring program. While at home, infants gained weight similarly to their inpatient controls inpatient, yet gained full oral skills at a significantly faster rate compared to when they were in the hospital.
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Brealey JK, Miller SE. SARS-CoV-2 has not been detected directly by electron microscopy in the endothelium of chilblain lesions. Br J Dermatol 2020; 184:186. [PMID: 33000462 PMCID: PMC9214016 DOI: 10.1111/bjd.19572] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 08/21/2020] [Accepted: 09/25/2020] [Indexed: 01/25/2023]
Abstract
Linked Article: Colmenero et al. Br J Dermatol 2020; 183:729–737.
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Miller SE, Tsuji K, Abrams RPM, Burke TR, Schneider JP. Uncoupling the Folding-Function Paradigm of Lytic Peptides to Deliver Impermeable Inhibitors of Intracellular Protein-Protein Interactions. J Am Chem Soc 2020; 142:19950-19955. [PMID: 33175531 PMCID: PMC8916162 DOI: 10.1021/jacs.0c07921] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Here, we describe the use of peptide backbone N-methylation as a new strategy to transform membrane-lytic peptides (MLPs) into cytocompatible intracellular delivery vehicles. The ability of lytic peptides to engage with cell membranes has been exploited for drug delivery to carry impermeable cargo into cells, but their inherent toxicity results in narrow therapeutic windows that limit their clinical translation. For most linear MLPs, a prerequisite for membrane activity is their folding at cell surfaces. Modification of their backbone with N-methyl amides inhibits folding, which directly correlates to a reduction in lytic potential but only minimally affects cell entry. We synthesized a library of N-methylated peptides derived from MLPs and conducted structure-activity studies that demonstrated the broad utility of this approach across different secondary structures, including both β-sheet and helix-forming peptides. Our strategy is highlighted by the delivery of a notoriously difficult class of protein-protein interaction inhibitors that displayed on-target activity within cells.
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Miller SE, Schneider JP. The effect of turn residues on the folding and cell-penetrating activity of β-hairpin peptides and applications toward protein delivery. Pept Sci (Hoboken) 2020; 112:e24125. [PMID: 34504991 PMCID: PMC8425381 DOI: 10.1002/pep2.24125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 05/25/2019] [Indexed: 11/11/2022]
Abstract
Cell-penetrating peptides (CPPs) are useful tools for the delivery of a wide variety of cargo into cells. Our lab has developed two classes of CPPs based on β-hairpin sequences, one that folds at the surface of cell membranes and the other that is intrinsically disordered. Although these peptides can effectively deliver different types of cargo, their use in protein delivery has been hindered due to the presence of non-natural D-proline within the central turn region of both sequences, which prohibits functionalizing proteins with the CPPs via standard expression protocols. In this work, we describe new CPPs that replace the non-natural turn region with natural turn motifs amenable to protein expression. We first investigate how these changes within the turn affect various CPP-related properties in the absence of protein cargo, and then generate protein fusions for intracellular delivery.
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Nagarkar RP, Miller SE, Zhong S, Pochan DJ, Schneider JP. Dynamic protein folding at the surface of stimuli-responsive peptide fibrils. Protein Sci 2018; 27:1243-1251. [PMID: 29493033 PMCID: PMC6032354 DOI: 10.1002/pro.3394] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 02/26/2018] [Accepted: 02/26/2018] [Indexed: 01/01/2023]
Abstract
The repetitive self-assembled structure of amyloid can serve as inspiration to design functional materials. Herein, we describe the design of α/β6, a peptide that contains distinct α-helical and β-structure forming domains. The folding and association state of each domain can be controlled by temperature. At low temperatures, the α-domain favors a coiled-coil state while the β-domain is unstructured. Irreversible fibril formation via self-assembly of the β-domain is triggered at high temperatures where the α-domain is unfolded. Resultant fibrils serve as templates upon which reversible coiled coil formation of the α-domain can be thermally controlled. At concentrations of α/β6 ≥ 2.5 wt%, the peptide forms a mechanically defined hydrogel highlighting the possibility of designing materials whose function can be actively modulated by controlling the folded state of proteins displayed from the surface of fibrils that constitute the gel.
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Miller SE, DeBoer MD, Scharf RJ. Executive functioning in low birth weight children entering kindergarten. J Perinatol 2018; 38:98-103. [PMID: 29048410 DOI: 10.1038/jp.2017.147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 07/14/2017] [Accepted: 08/11/2017] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Poor executive functioning is associated with life-long difficulty. Identification of children at risk for executive dysfunction is important for early intervention to improve neurodevelopmental outcomes. STUDY DESIGN This study is designed to examine relationships between birthweight and executive functioning in US children during kindergarten. Our hypothesis was that children with higher birthweights would have better executive function scores. We evaluated data from 17506 US children from the Early Childhood Longitudinal Study-Kindergarten 2011 cohort. Birthweight and gestational age were obtained by parental survey. Executive functions were directly assessed using the number reverse test and card sort test to measure working memory and cognitive flexibility, respectively. Teacher evaluations were used for additional executive functions. Data were analyzed using SAS to run all linear and logistical regressions. RESULTS For every kilogram of birthweight, scores of working memory increased by 1.47 (P<0.001) and cognitive flexibility increased by 0.28 (P<0.001) independent of gender, gestational age, parental education, and family income. Low birthweight infants were 1.5 times more likely to score in the bottom 20% of children on direct assessment OR=1.49 (CI 1.21-1.85) and OR=1.55 (CI 1.26-1.91). CONCLUSIONS Infants born low birthweight are at increased risk of poor executive functioning. As birthweight increases executive function scores improve, even among infants born normal weight. Further evaluation of this population including interventions and progression through school is needed.
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Banyikwa A, Miller SE, Krebs RA, Xiao Y, Carney JM, Braiman MS. Anhydrous Monoalkylguanidines in Aprotic and Nonpolar Solvents: Models for Deprotonated Arginine Side Chains in Membrane Environments. ACS OMEGA 2017; 2:7239-7252. [PMID: 31457300 PMCID: PMC6645140 DOI: 10.1021/acsomega.7b00281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 08/22/2017] [Indexed: 06/10/2023]
Abstract
In this study, the synthesis of crystalline dodecylguanidine free base and its spectroscopic characterization in nonpolar environments are described. IR as well as 1H and 15N NMR spectra of the free base dissolved in aprotic solvents are substantially different from the previously reported spectra of arginine, or other monoalkylguanidinium compounds, at high hydroxide concentrations. The current results provide improved modeling for the spectroscopic signals that would be expected from a deprotonated arginine in a nonpolar environment. On the basis of our spectra of the authentic dodecylguanidine free base, addition of large amounts of aqueous hydroxide to arginine or other monoalklyguanidinium salts does not deprotonate them. Instead, hydroxide addition leads to the formation of a guanidinium hydroxide complex, with a dissociation constant near ∼500 mM that accounts for the established arginine pK value of ∼13.7. We also report a method for synthesizing a compound containing both phenol and free-base guanidine groups, linked by a dodecyl chain that should be generalizable to other hydrocarbon linkers. Such alkyl-guanidine and phenolyl-alkyl-guanidine compounds can serve as small-molecule models for the conserved arginine-tyrosine groupings that have been observed in crystallographic structures of both microbial rhodopsins and G-protein-coupled receptors.
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Medina SH, Michie MS, Miller SE, Schnermann MJ, Schneider JP. Fluorous Phase-Directed Peptide Assembly Affords Nano-Peptisomes Capable of Ultrasound-Triggered Cellular Delivery. Angew Chem Int Ed Engl 2017; 56:11404-11408. [PMID: 28816007 PMCID: PMC5679192 DOI: 10.1002/anie.201704649] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Indexed: 01/02/2023]
Abstract
Here, we report the design, synthesis and efficacy of a new class of ultrasound (US)-sensitive self-assembled peptide-based nanoparticle. Peptisomes are prepared via templated assembly of a de novo designed peptide at the interface of fluorinated nanodroplets. Utilizing peptide assembly allows for facile particle synthesis, direct incorporation of bioactive sequences displayed from the particle corona, and the ability to easily encapsulate biologics during particle preparation using a mild solvent exchange procedure. Further, nano-peptisome size can be precisely controlled by simply modulating the starting peptide and fluorinated solvent concentrations during synthesis. Biomolecular cargo encapsulated within the particle core can be directly delivered to the cytoplasm of cells upon US-mediated rupture of the carrier. Thus, nano-peptisomes represent a novel class of US-activated carriers that can shuttle cell-impermeable biomacromolecules into cells with spatial and temporal precision.
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Medina SH, Michie MS, Miller SE, Schnermann MJ, Schneider JP. Fluorous Phase-Directed Peptide Assembly Affords Nano-Peptisomes Capable of Ultrasound-Triggered Cellular Delivery. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704649] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Hemmersbach-Miller M, Duronville J, Sethi S, Miller SE, Howell DN, Henshaw N, Alexander BD, Roberts JK. Hemorrhagic Herpes Simplex Virus Type 1 Nephritis: An Unusual Cause of Acute Allograft Dysfunction. Am J Transplant 2017; 17:287-291. [PMID: 27545820 DOI: 10.1111/ajt.14022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Revised: 08/16/2016] [Accepted: 08/17/2016] [Indexed: 01/25/2023]
Abstract
Interstitial nephritis due to viruses is well-described after solid organ transplantation. Viruses implicated include cytomegalovirus; BK polyomavirus; Epstein-Barr virus; and, less commonly, adenovirus. We describe a rare case of hemorrhagic allograft nephritis due to herpes simplex virus type 1 at 10 days after living donor kidney transplantation. The patient had a favorable outcome with intravenous acyclovir and reduction of immunosuppression.
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Miller SE, Nelson KL, Rodriguez RA. Microbiological Stability in Direct Potable Reuse Systems: Insights from Pilot-Scale Research Using Flow Cytometry and High-Throughput Sequencing. ACTA ACUST UNITED AC 2017. [DOI: 10.2175/193864717822153779] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Medina SH, Miller SE, Keim AI, Gorka AP, Schnermann MJ, Schneider JP. An Intrinsically Disordered Peptide Facilitates Non-Endosomal Cell Entry. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201510518] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Medina SH, Miller SE, Keim AI, Gorka AP, Schnermann MJ, Schneider JP. An Intrinsically Disordered Peptide Facilitates Non-Endosomal Cell Entry. Angew Chem Int Ed Engl 2016; 55:3369-72. [PMID: 26835878 DOI: 10.1002/anie.201510518] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 12/14/2015] [Indexed: 01/03/2023]
Abstract
Many cell-penetrating peptides (CPPs) fold at cell surfaces, adopting α- or β-structure that enable their intracellular transport. However, the same structural folds that facilitate cellular entry can also elicit potent membrane-lytic activity, limiting their use in delivery applications. Further, a distinct CPP can enter cells through many mechanisms, often leading to endosomal entrapment. Herein, we describe an intrinsically disordered peptide (CLIP6) that exclusively employs non-endosomal mechanisms to cross cellular membranes, while being remarkably biocompatible and serum-stable. We show that a single anionic glutamate residue is responsible for maintaining the disordered bioactive state of the peptide, defines its mechanism of cellular entry, and is central to its biocompatibility. CLIP6 can deliver membrane-impermeable cargo directly to the cytoplasm of cells, suggesting its broad utility for delivery of drug candidates limited by poor cell permeability and endosomal degradation.
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Heuck CJ, Jethava Y, Khan R, van Rhee F, Zangari M, Chavan S, Robbins K, Miller SE, Matin A, Mohan M, Ali SM, Stephens PJ, Ross JS, Miller VA, Davies F, Barlogie B, Morgan G. Inhibiting MEK in MAPK pathway-activated myeloma. Leukemia 2015; 30:976-80. [PMID: 26228812 PMCID: PMC4832073 DOI: 10.1038/leu.2015.208] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Tantibhedhyangkul J, Hawkins KC, Dai Q, Mu K, Dunn CN, Miller SE, Price TM. Expression of a mitochondrial progesterone receptor in human spermatozoa correlates with a progestin-dependent increase in mitochondrial membrane potential. Andrology 2014; 2:875-83. [PMID: 25187426 DOI: 10.1111/j.2047-2927.2014.00263.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 07/28/2014] [Accepted: 07/31/2014] [Indexed: 12/23/2022]
Abstract
The hyperactivation of human spermatozoa necessary for fertilization requires a substantial increase in cellular energy production. The factors responsible for increasing cellular energy remain poorly defined. This article proposes a role for a novel mitochondrial progesterone receptor (PR-M) in modulation of mitochondrial activity. Basic science studies demonstrate a 38 kDa protein with western blot analysis, consistent with PR-M; whereas imaging studies with confocal and immunoelectron microscopy demonstrate a PR on the mitochondria. Treatment with a PR-specific progestin shows increased mitochondrial membrane potential, not related to induction of an acrosome reaction. The increase in mitochondrial membrane potential was inhibited by a specific PR antagonist, but not affected by an inhibitor to the progesterone-dependent Catsper voltage-activated channel. In conclusion, these studies suggest expression of a novel mitochondrial PR in human spermatozoa with a progestin-dependent increase in mitochondrial activity. This mechanism may serve to enhance cellular energy production as the spermatozoa traverse the female genital tract being exposed to increasing concentrations of progesterone.
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Vorsino AE, Fortini LB, Amidon FA, Miller SE, Jacobi JD, Price JP, 'Ohukani'ohi'a Gon S, Koob GA. Modeling Hawaiian ecosystem degradation due to invasive plants under current and future climates. PLoS One 2014; 9:e102400. [PMID: 24991934 PMCID: PMC4081720 DOI: 10.1371/journal.pone.0102400] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Occupation of native ecosystems by invasive plant species alters their structure and/or function. In Hawaii, a subset of introduced plants is regarded as extremely harmful due to competitive ability, ecosystem modification, and biogeochemical habitat degradation. By controlling this subset of highly invasive ecosystem modifiers, conservation managers could significantly reduce native ecosystem degradation. To assess the invasibility of vulnerable native ecosystems, we selected a proxy subset of these invasive plants and developed robust ensemble species distribution models to define their respective potential distributions. The combinations of all species models using both binary and continuous habitat suitability projections resulted in estimates of species richness and diversity that were subsequently used to define an invasibility metric. The invasibility metric was defined from species distribution models with <0.7 niche overlap (Warrens I) and relatively discriminative distributions (Area Under the Curve >0.8; True Skill Statistic >0.75) as evaluated per species. Invasibility was further projected onto a 2100 Hawaii regional climate change scenario to assess the change in potential habitat degradation. The distribution defined by the invasibility metric delineates areas of known and potential invasibility under current climate conditions and, when projected into the future, estimates potential reductions in native ecosystem extent due to climate-driven invasive incursion. We have provided the code used to develop these metrics to facilitate their wider use (Code S1). This work will help determine the vulnerability of native-dominated ecosystems to the combined threats of climate change and invasive species, and thus help prioritize ecosystem and species management actions.
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Miller SE, Thomson PF, Arora PS. Synthesis of hydrogen-bond surrogate α-helices as inhibitors of protein-protein interactions. ACTA ACUST UNITED AC 2014; 6:101-116. [PMID: 24903885 DOI: 10.1002/9780470559277.ch130202] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The α-helix is a prevalent secondary structure in proteins and is critical in mediating protein-protein interactions (PPIs). Peptide mimetics that adopt stable helices have become powerful tools for the modulation of PPIs in vitro and in vivo. Hydrogen-bond surrogate (HBS) α-helices utilize a covalent bond in place of an N-terminal i to i+4 hydrogen bond and have been used to target and disrupt PPIs that become dysregulated in disease states. These compounds have improved conformational stability and cellular uptake as compared to their linear peptide counterparts. The protocol presented here describes current methodology for the synthesis of HBS α-helical mimetics. The solid-phase synthesis of HBS helices involves solid-phase peptide synthesis with three key steps involving incorporation of N-allyl functionality within the backbone of the peptide, coupling of a secondary amine, and a ring-closing metathesis step.
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Vorsino AE, Fortini LB, Amidon FA, Miller SE, Jacobi JD, Price JP, Gon S'O, Koob GA. Modeling Hawaiian ecosystem degradation due to invasive plants under current and future climates. PLoS One 2014; 9:e95427. [PMID: 24805254 PMCID: PMC4013088 DOI: 10.1371/journal.pone.0095427] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 03/26/2014] [Indexed: 11/18/2022] Open
Abstract
Occupation of native ecosystems by invasive plant species alters their structure and/or function. In Hawaii, a subset of introduced plants is regarded as extremely harmful due to competitive ability, ecosystem modification, and biogeochemical habitat degradation. By controlling this subset of highly invasive ecosystem modifiers, conservation managers could significantly reduce native ecosystem degradation. To assess the invasibility of vulnerable native ecosystems, we selected a proxy subset of these invasive plants and developed robust ensemble species distribution models to define their respective potential distributions. The combinations of all species models using both binary and continuous habitat suitability projections resulted in estimates of species richness and diversity that were subsequently used to define an invasibility metric. The invasibility metric was defined from species distribution models with <0.7 niche overlap (Warrens I) and relatively discriminative distributions (Area Under the Curve >0.8; True Skill Statistic >0.75) as evaluated per species. Invasibility was further projected onto a 2100 Hawaii regional climate change scenario to assess the change in potential habitat degradation. The distribution defined by the invasibility metric delineates areas of known and potential invasibility under current climate conditions and, when projected into the future, estimates potential reductions in native ecosystem extent due to climate-driven invasive incursion. We have provided the code used to develop these metrics to facilitate their wider use (Code S1). This work will help determine the vulnerability of native-dominated ecosystems to the combined threats of climate change and invasive species, and thus help prioritize ecosystem and species management actions.
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Mahon AB, Miller SE, Joy ST, Arora PS. Rational Design Strategies for Developing Synthetic Inhibitors of Helical Protein Interfaces. TOPICS IN MEDICINAL CHEMISTRY 2012. [DOI: 10.1007/978-3-642-28965-1_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
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Miller SE, Kallenbach NR, Arora PS. Reversible α-helix formation controlled by a hydrogen bond surrogate. Tetrahedron 2011; 68:4434-4437. [PMID: 23144512 DOI: 10.1016/j.tet.2011.12.068] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Strategically placed covalent linkages have been shown to stabilize helical conformations in short peptide sequences. Here we report the synthesis of a stabilized α-helix that utilizes an internal disulfide linkage. Structural analysis indicates that the dynamic nature of the disulfide bridge allows for the reversible formation of an α-helix through oxidation and reduction reactions.
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Jochim AL, Miller SE, Angelo NG, Arora PS. Evaluation of triazolamers as active site inhibitors of HIV-1 protease. Bioorg Med Chem Lett 2009; 19:6023-6. [PMID: 19800230 DOI: 10.1016/j.bmcl.2009.09.049] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 09/11/2009] [Accepted: 09/14/2009] [Indexed: 10/20/2022]
Abstract
Proteases typically recognize their peptide substrates in extended conformations. General approaches for designing protease inhibitors often consist of peptidomimetics that feature this conformation. Herein we discuss a combination of computational and experimental studies to evaluate the potential of triazole-linked beta-strand mimetics as inhibitors of HIV-1 protease activity.
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