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Cell Nov 2021NLRP6 is important in host defense by inducing functional outcomes including inflammasome activation and interferon production. Here, we show that NLRP6 undergoes...
NLRP6 is important in host defense by inducing functional outcomes including inflammasome activation and interferon production. Here, we show that NLRP6 undergoes liquid-liquid phase separation (LLPS) upon interaction with double-stranded RNA (dsRNA) in vitro and in cells, and an intrinsically disordered poly-lysine sequence (K350-354) of NLRP6 is important for multivalent interactions, phase separation, and inflammasome activation. Nlrp6-deficient or Nlrp6 mutant mice show reduced inflammasome activation upon mouse hepatitis virus or rotavirus infection, and in steady state stimulated by intestinal microbiota, implicating NLRP6 LLPS in anti-microbial immunity. Recruitment of ASC via helical assembly solidifies NLRP6 condensates, and ASC further recruits and activates caspase-1. Lipoteichoic acid, a known NLRP6 ligand, also promotes NLRP6 LLPS, and DHX15, a helicase in NLRP6-induced interferon signaling, co-forms condensates with NLRP6 and dsRNA. Thus, LLPS of NLRP6 is a common response to ligand stimulation, which serves to direct NLRP6 to distinct functional outcomes depending on the cellular context.
Topics: Amino Acid Sequence; Animals; CARD Signaling Adaptor Proteins; Hepatocytes; Inflammasomes; Intestines; Intrinsically Disordered Proteins; Lipopolysaccharides; Liver; Mice; Polylysine; Protein Binding; RNA Viruses; RNA, Double-Stranded; Receptors, Cell Surface; Signal Transduction; Teichoic Acids
PubMed: 34678144
DOI: 10.1016/j.cell.2021.09.032 -
Cold Spring Harbor Protocols Dec 2020Suspension cells can be prepared for staining by several different methods. A simple method for detecting intracellular antigens in cells that grow in suspension is to...
Suspension cells can be prepared for staining by several different methods. A simple method for detecting intracellular antigens in cells that grow in suspension is to attach the cells to a solid substrate before fixation. This can be achieved by the use of a cytocentrifuge. For surface staining, suspension cells can be attached to slides by cross-linking with poly-l-lysine. Lysine can be polymerized to any desired length, and poly-l-lysine will bind to most solid supports through its charged side chains. The positively charged polymer will provide a site for binding of cells (which carry an overall negative charge). Although this cross-link is not covalent, it is sufficiently strong for most cell-staining techniques.
Topics: Animals; Cell Adhesion; Cells, Cultured; Centrifugation; Histocytochemistry; Humans; Polylysine; Reproducibility of Results; Staining and Labeling
PubMed: 33262234
DOI: 10.1101/pdb.prot099622 -
Angewandte Chemie (International Ed. in... Sep 2019In nature, dynamic processes are ubiquitous and often characterized by adaptive, transient behavior. Herein, we present the development of a transient bowl-shaped... (Review)
Review
In nature, dynamic processes are ubiquitous and often characterized by adaptive, transient behavior. Herein, we present the development of a transient bowl-shaped nanoreactor system, or stomatocyte, the properties of which are mediated by molecular interactions. In a stepwise fashion, we couple motility to a dynamic process, which is maintained by transient events; namely, binding and unbinding of adenosine triphosphate (ATP). The surface of the nanosystem is decorated with polylysine (PLL), and regulation is achieved by addition of ATP. The dynamic interaction between PLL and ATP leads to an increase in the hydrophobicity of the PLL-ATP complex and subsequently to a collapse of the polymer; this causes a narrowing of the opening of the stomatocytes. The presence of the apyrase, which hydrolyzes ATP, leads to a decrease of the ATP concentration, decomplexation of PLL, and reopening of the stomatocyte. The competition between ATP input and consumption gives rise to a transient state that is controlled by the out-of-equilibrium process.
Topics: Adenosine Triphosphate; Animals; Artificial Cells; Cell Shape; Erythrocytes; Humans; Hydrophobic and Hydrophilic Interactions; Nanostructures; Nanotechnology; Polylysine
PubMed: 31267638
DOI: 10.1002/anie.201906331 -
Molecular Pharmaceutics Oct 2021Polylysine and materials that integrate lysine form promising drug delivery platforms. As a cationic macromolecule, a polylysine polymer electrostatically interacts with... (Review)
Review
Polylysine and materials that integrate lysine form promising drug delivery platforms. As a cationic macromolecule, a polylysine polymer electrostatically interacts with cells and is efficiently internalized, thereby enabling intracellular delivery. Although polylysine is intrinsically pH-responsive, the conjugation with different functional groups imparts smart, stimuli-responsive traits by adding pH-, temperature-, hypoxia-, redox-, and enzyme-responsive features for enhanced delivery of therapeutic agents. Because of such characteristics, polylysine has been used to deliver various cargos such as small-molecule drugs, genes, proteins, and imaging agents. Furthermore, modifying contrast agents with polylysine has been shown to improve performance, including increasing cellular uptake and stability. In this review, the use of lysine residues, peptides, and polymers in various drug delivery systems has been discussed comprehensively to provide insight into the design and robust manufacturing of lysine-based delivery platforms.
Topics: Drug Delivery Systems; Humans; Lysine; Polylysine
PubMed: 34519501
DOI: 10.1021/acs.molpharmaceut.1c00474 -
Molecules (Basel, Switzerland) Oct 2019The cellular transport process of DNA is hampered by cell membrane barriers, and hence, a delivery vehicle is essential for realizing the potential benefits of gene... (Review)
Review
The cellular transport process of DNA is hampered by cell membrane barriers, and hence, a delivery vehicle is essential for realizing the potential benefits of gene therapy to combat a variety of genetic diseases. Virus-based vehicles are effective, although immunogenicity, toxicity and cancer formation are among the major limitations of this approach. Cationic polymers, such as polyethyleneimine are capable of condensing DNA to nanoparticles and facilitate gene delivery. Lack of biodegradation of polymeric gene delivery vehicles poses significant toxicity because of the accumulation of polymers in the tissue. Many attempts have been made to develop biodegradable polymers for gene delivery by modifying existing polymers and/or using natural biodegradable polymers. This review summarizes mechanistic aspects of gene delivery and the development of biodegradable polymers for gene delivery.
Topics: Animals; Biological Transport; Chitosan; Dextrans; Endosomes; Gene Transfer Techniques; Genetic Therapy; Glucans; Humans; Hyaluronic Acid; Hydrolysis; Lysosomes; Nanoparticles; Polyethyleneimine; Polylysine
PubMed: 31627389
DOI: 10.3390/molecules24203744 -
The Urologic Clinics of North America Nov 2020Relatively simple, synthetic, double-stranded RNAs can be powerful viral pathogen-associated molecular pattern (PAMP) mimics, inducing a panoply of antiviral and... (Review)
Review
Relatively simple, synthetic, double-stranded RNAs can be powerful viral pathogen-associated molecular pattern (PAMP) mimics, inducing a panoply of antiviral and antitumor responses that act at multiple stages of host defense. Their mechanisms of action and uses are beginning to be understood, alone, in combination with other therapeutics, or as novel PAMP-adjuvants providing the critical danger signal that has been missing from most cancer and other modern vaccines. Dose, timing, route of administration combinations, and other clinical variables can have a critical impact on immunogenicity. This article reviews advances in the use of polyinosinic-polycytidylic acid and derivatives, in particular poly-ICLC.
Topics: Adjuvants, Immunologic; Cancer Vaccines; Carboxymethylcellulose Sodium; Clinical Trials as Topic; Humans; Immunologic Factors; Male; Pathogen-Associated Molecular Pattern Molecules; Poly I-C; Polylysine; Prostatic Neoplasms; RNA, Double-Stranded
PubMed: 33446322
DOI: 10.1016/j.ucl.2020.10.003 -
Biomaterials Science Jun 2024The treatment of various types of wounds such as dermal wounds, multidrug resistant bacteria-infected wounds, and chronic diabetic wounds is one of the critical... (Review)
Review
The treatment of various types of wounds such as dermal wounds, multidrug resistant bacteria-infected wounds, and chronic diabetic wounds is one of the critical challenges facing healthcare systems. Delayed wound healing can impose a remarkable burden on patients and health care professionals. In this case, given their unique three-dimensional porous structure, biocompatibility, high hydrophilicity, capability to provide a moist environment while absorbing wound exudate, permeability to both gas and oxygen, and tunable mechanical properties, hydrogels with antibacterial function are one of the most promising candidates for wound healing applications. Polylysine is a cationic polymer with the advantages of inherent antibacterial properties, biodegradability, and biocompatibility. Therefore, its utilization to engineer antibacterial hydrogels for accelerating wound healing is of great interest. In this review, we initially discuss polylysine properties, and then focus on the most recent advances in polylysine-containing hydrogels (since 2016) prepared using various chemical and physical crosslinking methods for hemostasis and wound healing applications. Finally, the challenges and future directions in the engineering of these antibacterial hydrogels for wound healing are discussed.
Topics: Hydrogels; Wound Healing; Polylysine; Anti-Bacterial Agents; Humans; Animals; Hemostatics; Hemostasis
PubMed: 38747970
DOI: 10.1039/d3bm01792c -
Soft Matter Sep 2022The α-helix has a significant role in protein function and structure because of its rigidity. In this study, we investigate the persistence length, , of α-helical...
The α-helix has a significant role in protein function and structure because of its rigidity. In this study, we investigate the persistence length, , of α-helical poly-L-lysine, PLL, for two molecular weights. PLL experiences a random coil-helix transition as the pH is raised from 7 to 12. Using light scattering experiments to determine the radius of gyration (), hydrodynamic radius, (), the shape factor (/), and second virial coefficient (), and circular dichroism to determine the helical content, we find the structure and of PLL as a function of pH (7.4-11.4) and ionic strength (100-166 mM). With increasing pH, we find an increase in from 2 nm to 15-21 nm because of α-helix formation. We performed dissipative particle dynamics (DPD) simulations and found a similar increase in . While this is less than that predicted by molecular dynamics simulations, it is consistent with other experimental results, which quantify the mechanics of α-helices. By determining the mechanics of helical polypeptides like PLL, we can further understand their implications to protein function.
Topics: Circular Dichroism; Molecular Weight; Peptides; Polylysine; Protein Conformation, alpha-Helical
PubMed: 36039676
DOI: 10.1039/d2sm00921h -
Biomaterials Science Sep 2023Development of novel therapeutic agents that possess different anticancer mechanisms from the traditional antitumor drugs is highly attractive as no medication can cure...
Development of novel therapeutic agents that possess different anticancer mechanisms from the traditional antitumor drugs is highly attractive as no medication can cure all types of cancers. Herein, we report a rational design of antitumor lipo-polylysine polymers as synthetic mimics of biosynthetic lipopeptide surfactants featuring antimicrobial or cytotoxic activities for cancer therapy. The optimal polymer shows a wide range of anticancer activities against multiple cancer cells, including highly metastatic and drug-resistant ones, but low toxicity to normal cells. Mechanism studies show that the optimal polymer can interact with the membrane of cancer cells and induce cell necrosis by triggering cell membrane perforation, which is different from the therapeutic mechanisms of traditional anticancer drugs. studies imply that the optimal polymer efficiently inhibits tumor growth without causing obvious side effects on a C26 graft tumor model. Overall, the lipopeptide-mimicking lipo-polylysine with the advantages of easy synthesis and low cost provides a new anticancer strategy with high efficacy and biocompatibility.
Topics: Humans; Polylysine; Antineoplastic Agents; Neoplasms; Lipopeptides; Polymers
PubMed: 37605903
DOI: 10.1039/d3bm01099f -
Investigative Ophthalmology & Visual... Jan 2022To determine the amoebicidal activity of functionalized poly-epsilon-lysine hydrogels (pɛK+) against Acanthamoeba castellanii.
PURPOSE
To determine the amoebicidal activity of functionalized poly-epsilon-lysine hydrogels (pɛK+) against Acanthamoeba castellanii.
METHODS
A. castellanii trophozoites and cysts were grown in the presence of pɛK solution (0-2.17 mM), pɛK or pɛK+ hydrogels, or commercial hydrogel contact lens (CL) for 24 hours or 7 days in PBS or Peptone-Yeast-Glucose (PYG) media (nutrient-deplete or nutrient-replete cultures, respectively). Toxicity was determined using propidium iodide and imaged using fluorescence microscopy. Ex vivo porcine corneas were inoculated with A. castellanii trophozoites ± pɛK, pɛK+ hydrogels or commercial hydrogel CL for 7 days. Corneal infection was assessed by periodic acid-Schiff staining and histologic analysis. Regrowth of A. castellanii from hydrogel lenses and corneal discs at 7 days was assessed using microscopy and enumeration.
RESULTS
The toxicity of pɛK+ hydrogels resulted in the death of 98.52% or 83.31% of the trophozoites at 24 hours or 7 days, respectively. The toxicity of pɛK+ hydrogels resulted in the death of 70.59% or 82.32% of the cysts in PBS at 24 hours or 7 days, respectively. Cysts exposed to pɛK+ hydrogels in PYG medium resulted in 75.37% and 87.14% death at 24 hours and 7 days. Ex vivo corneas infected with trophozoites and incubated with pɛK+ hydrogels showed the absence of A. castellanii in the stroma, with no regrowth from corneas or pɛK+ hydrogel, compared with infected-only corneas and those incubated in presence of commercial hydrogel CL.
CONCLUSIONS
pɛK+ hydrogels demonstrated pronounced amoebicidal and cysticidal activity against A. castellanii. pɛK+ hydrogels have the potential for use as CLs that could minimize the risk of CL-associated Acanthamoeba keratitis.
Topics: Acanthamoeba Keratitis; Acanthamoeba castellanii; Amebicides; Animals; Cells, Cultured; Contact Lens Solutions; Cornea; Disease Models, Animal; Epithelium, Corneal; Eye Infections, Parasitic; Humans; Hydrogels; Microscopy, Fluorescence; Polylysine; Swine; Trophozoites
PubMed: 34994769
DOI: 10.1167/iovs.63.1.11