scholarly journals Desiccation-induced fibrous condensation of CAHS protein from an anhydrobiotic tardigrade

2021 ◽  
Author(s):  
Maho Yagi-Utsumi ◽  
Kazuhiro Aoki ◽  
Hiroki Watanabe ◽  
Chihong Song ◽  
Seiji Nishimura ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Sol Gel ◽  
Protein A ◽  
Protective Mechanisms ◽  
Self Assembling ◽  
Protein Functions ◽  
Sol Gel Transition ◽  
Helical Region

Anhydrobiosis is one of the most extensively studied forms of cryptobiosis that is induced in certain organisms as a response to desiccation. Anhydrobiotic species has been hypothesized to produce substances that can protect their biological components and/or cell membranes without water. In extremotolerant tardigrades, highly hydrophilic and heat-soluble protein families, cytosolic abundant heat-soluble (CAHS) proteins, have been identified, which are postulated to be integral parts of the tardigrades' response to desiccation. However, the molecular mechanisms underlying these protein functions remain to be fully elucidated. In this study, in vitro and in vivo characterizations of the self-assembling property of CAHS1 protein, a major isoform of CAHS proteins from Ramazzottius varieornatus, using a series of spectroscopic and microscopic techniques. Our in vitro observations showed that CAHS1 proteins homo-oligomerized via the C-terminal α-helical region and formed a hydrogel as their concentration increased, and that these molecular assembling processes were reversible. Furthermore, our in vivo observations demonstrated that the overexpressed CAHS1 proteins formed condensates under desiccation-mimicking conditions. These data strongly suggested that, upon drying, the CAHS1 proteins form oligomers and eventually underwent sol-gel transition in tardigrade cytosols. Thus, it is proposed that the CAHS1 proteins form the cytosolic fibrous condensates, which presumably have variable mechanisms for the desiccation tolerance of tardigrades. These findings provide insights into the protective mechanisms involved in the anhydrobiosis of tardigrades.

scholarly journals Desiccation-induced fibrous condensation of CAHS protein from an anhydrobiotic tardigrade

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maho Yagi-Utsumi ◽  
Kazuhiro Aoki ◽  
Hiroki Watanabe ◽  
Chihong Song ◽  
Seiji Nishimura ◽  
...  
Keyword(s):  
Sol Gel ◽  
Protein A ◽  
Extreme Environments ◽  
Self Assembling ◽  
Protein Functions ◽  
Sol Gel Transition ◽  
Microscopic Techniques ◽  
Helical Region

AbstractAnhydrobiosis, one of the most extensively studied forms of cryptobiosis, is induced in certain organisms as a response to desiccation. Anhydrobiotic species has been hypothesized to produce substances that can protect their biological components and/or cell membranes without water. In extremotolerant tardigrades, highly hydrophilic and heat-soluble protein families, cytosolic abundant heat-soluble (CAHS) proteins, have been identified, which are postulated to be integral parts of the tardigrades’ response to desiccation. In this study, to elucidate these protein functions, we performed in vitro and in vivo characterizations of the reversible self-assembling property of CAHS1 protein, a major isoform of CAHS proteins from Ramazzottius varieornatus, using a series of spectroscopic and microscopic techniques. We found that CAHS1 proteins homo-oligomerized via the C-terminal α-helical region and formed a hydrogel as their concentration increased. We also demonstrated that the overexpressed CAHS1 proteins formed condensates under desiccation-mimicking conditions. These data strongly suggested that, upon drying, the CAHS1 proteins form oligomers and eventually underwent sol–gel transition in tardigrade cytosols. Thus, it is proposed that the CAHS1 proteins form the cytosolic fibrous condensates, which presumably have variable mechanisms for the desiccation tolerance of tardigrades. These findings provide insights into molecular strategies of organisms to adapt to extreme environments.

scholarly journals Preparation and Characterization of Salt-Mediated Injectable Thermosensitive Chitosan/Pectin Hydrogels for Cell Embedding and Culturing

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2674
Author(s):  
Giulia Morello ◽  
Alessandro Polini ◽  
Francesca Scalera ◽  
Riccardo Rizzo ◽  
Giuseppe Gigli ◽  
...  
Keyword(s):  
Sol Gel ◽  
Polymer Network ◽  
Cell Encapsulation ◽  
High Water ◽  
Biological Tissues ◽  
Culture Conditions ◽  
Interpenetrating Polymer Network ◽  
Sol Gel Transition

In recent years, growing attention has been directed to the development of 3D in vitro tissue models for the study of the physiopathological mechanisms behind organ functioning and diseases. Hydrogels, acting as 3D supporting architectures, allow cells to organize spatially more closely to what they physiologically experience in vivo. In this scenario, natural polymer hybrid hydrogels display marked biocompatibility and versatility, representing valid biomaterials for 3D in vitro studies. Here, thermosensitive injectable hydrogels constituted by chitosan and pectin were designed. We exploited the feature of chitosan to thermally undergo sol–gel transition upon the addition of salts, forming a compound that incorporates pectin into a semi-interpenetrating polymer network (semi-IPN). Three salt solutions were tested, namely, beta-glycerophosphate (βGP), phosphate buffer (PB) and sodium hydrogen carbonate (SHC). The hydrogel formulations (i) were injectable at room temperature, (ii) gelled at 37 °C and (iii) presented a physiological pH, suitable for cell encapsulation. Hydrogels were stable in culture conditions, were able to retain a high water amount and displayed an open and highly interconnected porosity and suitable mechanical properties, with Young’s modulus values in the range of soft biological tissues. The developed chitosan/pectin system can be successfully used as a 3D in vitro platform for studying tissue physiopathology.

Thermo-sensitive hydrogel PLGA-PEG-PLGA as a vaccine delivery system for intramuscular immunization

2016 ◽  
Vol 31 (6) ◽  
pp. 923-932 ◽  
Author(s):  
Xiaoyan Wang ◽  
Yu Zhang ◽  
Wei Xue ◽  
Hong Wang ◽  
Xiaozhong Qiu ◽  
...  
Keyword(s):  
Delivery System ◽  
Sol Gel ◽  
Vaccine Delivery ◽  
In Vitro Release ◽  
Vaccine Delivery System ◽  
Th1 And Th2 Cytokines ◽  
Specific Igg ◽  
Sol Gel Transition

In this work, we explored the potential of thermo-sensitive PLGA-PEG-PLGA with sol-gel transition temperature around 32℃ as an intramuscular vaccine delivery system by using ovalbumin as a model antigen. First, in vitro release test showed that the PLGA-PEG-PLGA-deriving hydrogels could release ovalbumin in vitro in a more sustainable way. From fluorescence living imaging, 50–200 mg/mL of PLGA-PEG-PLGA formulations could release antigen in a sustainable manner in vivo, suggesting that the PLGA-PEG-PLGA hydrogel worked as an antigen-depot. Further, the sustainable antigen release from the PLGA-PEG-PLGA hydrogels increased antigen availability in the spleens of the immunized mice. The intramuscular immunization results showed that 50–200 mg/mL of PLGA-PEG-PLGA formulations promoted significantly more potent antigen-specific IgG immune response. In addition, 200 mg/mL of PLGA-PEG-PLGA formulation significantly enhanced the secretion of both Th1 and Th2 cytokines. From in vitro splenocyte proliferation assay, 50–200 mg/mL of PLGA-PEG-PLGA formulations all initiated significantly higher splenocyte activation. These results indicate that the thermo-sensitive and injectable PLGA-PEG-PLGA hydrogels (particularly, 200 mg/mL of PLGA-PEG-PLGA-based hydrogel) own promising potential as an intramuscular vaccine delivery system.

Effect of Mixing Bioactive Nanoceramics with a Thermosensitive Hydrogel as Bone Substitute

2012 ◽  
Vol 622-623 ◽  
pp. 1794-1798 ◽  
Author(s):  
Po Liang Lai ◽  
Ding Wei Hong ◽  
Carl Tsai Yu Lin ◽  
Lih Huei Chen ◽  
Wen Jer Chen ◽  
...  
Keyword(s):  
Animal Studies ◽  
Ph Value ◽  
Sol Gel ◽  
Degradation Process ◽  
Thermosensitive Hydrogel ◽  
Composite Gels ◽  
Bone Graft Substitutes ◽  
Sol Gel Transition

The composite of methoxy polyethylene glycol (mPEG) and poly(lactic-co- glycolic acid) (PLGA) thermosensitive hydrogel mixed with different mass raio of hydroxyapatite and β-tricalcium phosphate (β-TCP) were used as bone graft substitutes. The physical properties of a series of composite gels, including the critical micelle concentration (CMC), particle sizes, zeta potential, rheological behavior, morphology of composite gels, and sol–gel transition, were characterized in vitro. These composite gels could form a gel at body temperature and could be controlled easily at room temperature. During the in vitro degradation process, composite gels demonstrated a slight decrease in pH value, a slower degradation rate, less toxicity, and a higher cell survival rate. The biocompatibility of the composite gels was validated by hemolysis test. In vivo animal studies demonstrated both radiographic and gross bone union when the ratio of HAP/ β-TCP was 7:3.

scholarly journals Upregulation of Na+ and Ca2+ transporters in arterial smooth muscle from ouabain-induced hypertensive rats

2010 ◽  
Vol 298 (1) ◽  
pp. H263-H274 ◽  
Author(s):  
Maria V. Pulina ◽  
Alessandra Zulian ◽  
Roberto Berra-Romani ◽  
Olga Beskina ◽  
Amparo Mazzocco-Spezzia ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Smooth Muscle ◽  
Molecular Mechanisms ◽  
Transient Receptor Potential ◽  
Protein A ◽  
Receptor Potential ◽  
Atpase Inhibitor ◽  
Rna Knockdown

Prolonged ouabain administration (25 μg·kg−1·day−1 for 5 wk) induces “ouabain hypertension” (OH) in rats, but the molecular mechanisms by which ouabain elevates blood pressure are unknown. Here, we compared Ca2+ signaling in mesenteric artery smooth muscle cells (ASMCs) from normotensive (NT) and OH rats. Resting cytosolic free Ca2+ concentration ([Ca2+]cyt; measured with fura-2) and phenylephrine-induced Ca2+ transients were augmented in freshly dissociated OH ASMCs. Immunoblots revealed that the expression of the ouabain-sensitive α2-subunit of Na+ pumps, but not the predominant, ouabain-resistant α1-subunit, was increased (2.5-fold vs. NT ASMCs) as was Na+/Ca2+ exchanger-1 (NCX1; 6-fold vs. NT) in OH arteries. Ca2+ entry, activated by sarcoplasmic reticulum (SR) Ca2+ store depletion with cyclopiazonic acid (SR Ca2+-ATPase inhibitor) or caffeine, was augmented in OH ASMCs. This reflected an augmented expression of 2.5-fold in OH ASMCs of C-type transient receptor potential TRPC1, an essential component of store-operated channels (SOCs); two other components of some SOCs were not expressed (TRPC4) or were not upregulated (TRPC5). Ba2+ entry activated by the diacylglycerol analog 1-oleoyl-2-acetyl- sn-glycerol [a measure of receptor-operated channel (ROC) activity] was much greater in OH than NT ASMCs. This correlated with a sixfold upregulation of TRPC6 protein, a ROC family member. Importantly, in primary cultured mesenteric ASMCs from normal rats, 72-h treatment with 100 nM ouabain significantly augmented NCX1 and TRPC6 protein expression and increased resting [Ca2+]cyt and ROC activity. SOC activity was also increased. Silencer RNA knockdown of NCX1 markedly downregulated TRPC6 and eliminated the ouabain-induced augmentation; silencer RNA knockdown of TRPC6 did not affect NCX1 expression but greatly attenuated its upregulation by ouabain. Clearly, NCX1 and TRPC6 expression are interrelated. Thus, prolonged ouabain treatment upregulates the Na+ pump α2-subunit-NCX1-TRPC6 (ROC) Ca2+ signaling pathway in arterial myocytes in vitro as well as in vivo. This may explain the augmented myogenic responses and enhanced phenylephrine-induced vasoconstriction in OH arteries ( 83 ) as well as the high blood pressure in OH rats.

scholarly journals Lsr2 of Mycobacterium Represents a Novel Class of H-NS-Like Proteins

2008 ◽  
Vol 190 (21) ◽  
pp. 7052-7059 ◽  
Author(s):  
Blair R. G. Gordon ◽  
Robin Imperial ◽  
Linru Wang ◽  
William Wiley Navarre ◽  
Jun Liu
Keyword(s):  
Mycobacterium Smegmatis ◽  
Molecular Mechanisms ◽  
Basic Protein ◽  
Protein A ◽  
Functional Equivalence ◽  
Gram Negative Bacteria ◽  
Gram Positive Bacteria ◽  
Functional Analog

ABSTRACT Lsr2 is a small, basic protein present in Mycobacterium and related actinomycetes. Our previous in vitro biochemical studies showed that Lsr2 is a DNA-bridging protein, a property shared by H-NS-like proteins in gram-negative bacteria. Here we present in vivo evidence based on genetic complementation experiments that Lsr2 is a functional analog of H-NS, the first such protein identified in gram-positive bacteria. We show that lsr2 can complement the phenotypes related to hns mutations in Escherichia coli, including β-glucoside utilization, mucoidy, motility, and hemolytic activity. We also show that Lsr2 binds specifically to H-NS-regulated genes and the repression of hlyE by Lsr2 can be partially eliminated by overexpression of slyA, suggesting that the molecular mechanisms of Lsr2 repression and depression are similar to those of H-NS. The functional equivalence of these two proteins is further supported by the ability of hns to complement the lsr2 phenotype in Mycobacterium smegmatis. Taken together, our results demonstrate unequivocally that Lsr2 is an H-NS-like protein.

scholarly journals Thermosensitive Poly(DHSe/PEG/PPG Urethane)-Based Hydrogel Extended Remdesivir Application in Ophthalmic Medication

Pharmaceutics ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 50
Author(s):  
Sennan Xu ◽  
Lingjie Ke ◽  
Sichen Zhao ◽  
Zhiguo Li ◽  
Yang Xiao ◽  
...  
Keyword(s):  
Sol Gel ◽  
In Vitro Release ◽  
Water Soluble ◽  
Prolonged Release ◽  
In Situ Gel ◽  
Sol Gel Transition ◽  
Novel Coronavirus

The spread of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the coronavirus disease 2019 (COVID-19) outbreak beginning in March 2020. Currently, there is a lack of suitable dose formulations that interrupt novel coronavirus transmission via corneal and conjunctival routes. In the present study, we developed and evaluated a thermosensitive gelling system based on a selenium-containing polymer for topical ocular continuous drug release. In detail, di-(1-hydroxylundecyl) selenide (DHSe), poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) were polymerized to form poly(DHSe/PEG/PPG urethane). The polymer was used to carry poorly water-soluble remdesivir (RDV) at room temperature to form the final thermosensitive in situ gel, which exhibited a typical sol-gel transition at 35 °C. The formed polymer was further characterized by rheology, thermology, and scanning electron microscopy. In vitro release studies and in vivo retention and penetration tests indicated that the thermogel provided the prolonged release of RDV. The RDV-loaded in situ gel was proven to be non-biotoxic against human corneal epithelial cells, with good ocular tolerance and biocompatibility in rabbit eyes.

Tantalum Oxide Nanoparticles as Versatile Contrast Agents for X-ray Computed Tomography

2020 ◽  
Author(s):  
Shatadru Chakravarty ◽  
Jeremy Hix ◽  
Kaitlyn Wieweora ◽  
Maximilian Volk ◽  
Elizabeth Kenyon ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Contrast Agents ◽  
Mesoporous Silica Nanoparticles ◽  
Sol Gel ◽  
Tantalum Oxide ◽  
High Signal ◽  
Drug Delivery Vehicles ◽  
X Ray Computed

Here we describe the synthesis, characterization and in vitro and in vivo performance of a series of tantalum oxide (TaOx) based nanoparticles (NPs) for computed tomography (CT). Five distinct versions of 9-12 nm diameter silane coated TaOx nanocrystals (NCs) were fabricated by a sol-gel method with varying degrees of hydrophilicity and with or without fluorescence, with the highest reported Ta content to date (78%). Highly hydrophilic NCs were left bare and were evaluated in vivo in mice for micro-CT of full body vasculature, where following intravenous injection, TaOx NCs demonstrate high CT contrast, circulation in blood for ~ 3 h, and eventual accumulation in RES organs; and following injection locally in the mammary gland, where the full ductal tree structure can be clearly delineated. Partially hydrophilic NCs were encapsulated within mesoporous silica nanoparticles (MSNPs; TaOx@MSNPs) and hydrophobic NCs were encapsulated within poly(lactic-co-glycolic acid) (PLGA; TaOx@PLGA) NPs, serving as potential CT-imagable drug delivery vehicles. Bolus intramuscular injections of TaOx@PLGA NPs and TaOx@MSNPs to mimic the accumulation of NPs at a tumor site produce high signal enhancement in mice. In vitro studies on bare NCs and formuated NPs demonstrate high cytocompatibility and low dissolution of TaOx. This work solidifies that TaOx-based NPs are versatile contrast agents for CT.

Flavonoids as P-gp Inhibitors: A Systematic Review of SARs

2019 ◽  
Vol 26 (25) ◽  
pp. 4799-4831 ◽  
Author(s):  
Jiahua Cui ◽  
Xiaoyang Liu ◽  
Larry M.C. Chow
Keyword(s):  
Molecular Mechanisms ◽  
Metastatic Cancer ◽  
Drug Candidates ◽  
Chemical Structures ◽  
Transporter Family ◽  
Promising Area ◽  
New Generation ◽  
Nontoxic Inhibitors

P-glycoprotein, also known as ABCB1 in the ABC transporter family, confers the simultaneous resistance of metastatic cancer cells towards various anticancer drugs with different targets and diverse chemical structures. The exploration of safe and specific inhibitors of this pump has always been the pursuit of scientists for the past four decades. Naturally occurring flavonoids as benzopyrone derivatives were recognized as a class of nontoxic inhibitors of P-gp. The recent advent of synthetic flavonoid dimer FD18, as a potent P-gp modulator in reversing multidrug resistance both in vitro and in vivo, specifically targeted the pseudodimeric structure of the drug transporter and represented a new generation of inhibitors with high transporter binding affinity and low toxicity. This review concerned the recent updates on the structure-activity relationships of flavonoids as P-gp inhibitors, the molecular mechanisms of their action and their ability to overcome P-gp-mediated MDR in preclinical studies. It had crucial implications on the discovery of new drug candidates that modulated the efflux of ABC transporters and also provided some clues for the future development in this promising area.

Approach in improving potency and selectivity of kinase inhibitors: Allosteric kinase inhibitors

2020 ◽  
Vol 21 ◽  
Author(s):  
Shangfei Wei ◽  
Tianming Zhao ◽  
Jie Wang ◽  
Xin Zhai
Keyword(s):  
Protein Interactions ◽  
Kinase Inhibitors ◽  
Binding Modes ◽  
Allosteric Inhibitors ◽  
Wide Range ◽  
Allosteric Sites ◽  
Protein Functions ◽  
Regulate Protein

: Allostery is an efficient and particular regulatory mechanism to regulate protein functions. Different from conserved orthosteric sites, allosteric sites have distinctive functional mechanism to form the complex regulatory network. In drug discovery, kinase inhibitors targeting the allosteric pockets have received extensive attention for the advantages of high selectivity and low toxicity. The approval of trametinib as the first allosteric inhibitor validated that allosteric inhibitors could be used as effective therapeutic drugs for treatment of diseases. To date, a wide range of allosteric inhibitors have been identified. In this perspective, we outline different binding modes and potential advantages of allosteric inhibitors. In the meantime, the research processes of typical and novel allosteric inhibitors are described briefly in terms of structureactivity relationships, ligand-protein interactions and in vitro and in vivo activity. Additionally, challenges as well as opportunities are presented.

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