scholarly journals Connexin hemichannel inhibition ameliorates epidermal pathology in a mouse model of keratitis ichthyosis deafness syndrome

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Caterina Sellitto ◽  
Leping Li ◽  
Thomas W. White
Keyword(s):  
Mouse Model ◽  
Skin Diseases ◽  
Point Mutations ◽  
Childhood Mortality ◽  
Therapeutic Interventions ◽  
Flufenamic Acid ◽  
Gene Encoding ◽  
Connexin Hemichannel

AbstractMutations in five different genes encoding connexin channels cause eleven clinically defined human skin diseases. Keratitis ichthyosis deafness (KID) syndrome is caused by point mutations in the GJB2 gene encoding Connexin 26 (Cx26) which result in aberrant activation of connexin hemichannels. KID syndrome has no cure and is associated with bilateral hearing loss, blinding keratitis, palmoplantar keratoderma, ichthyosiform erythroderma and a high incidence of childhood mortality. Here, we have tested whether a topically applied hemichhanel inhibitor (flufenamic acid, FFA) could ameliorate the skin pathology associated with KID syndrome in a transgenic mouse model expressing the lethal Cx26-G45E mutation. We found that FFA blocked the hemichannel activity of Cx26-G45E in vitro, and substantially reduced epidermal pathology in vivo, compared to untreated, or vehicle treated control animals. FFA did not reduce the expression of mutant connexin hemichannel protein, and cessation of FFA treatment allowed disease progression to continue. These results suggested that aberrant hemichannel activity is a major driver of skin disease in KID syndrome, and that the inhibition of mutant hemichannel activity could provide an attractive target to develop novel therapeutic interventions to treat this incurable disease.

scholarly journals Improvement of α-Amylase Production by Modulation of Ribosomal Component Protein S12 in Bacillus subtilis 168

2006 ◽  
Vol 72 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Kazuhiko Kurosawa ◽  
Takeshi Hosaka ◽  
Norimasa Tamehiro ◽  
Takashi Inaoka ◽  
Kozo Ochi
Keyword(s):  
Bacillus Subtilis ◽  
Antibiotic Production ◽  
Point Mutations ◽  
Protease Production ◽  
Gene Encoding ◽  
Translational Activity ◽  
Amylase Production ◽  
Ribosomal Protein S12

ABSTRACT The capacity of ribosomal modification to improve antibiotic production by Streptomyces spp. has already been demonstrated. Here we show that introduction of mutations that produce streptomycin resistance (str) also enhances α-amylase (and protease) production by a strain of Bacillus subtilis as estimated by measuring the enzyme activity. The str mutations are point mutations within rpsL, the gene encoding the ribosomal protein S12. In vivo as well as in vitro poly(U)-directed cell-free translation systems showed that among the various rpsL mutations K56R (which corresponds to position 42 in E. coli) was particularly effective at enhancing α-amylase production. Cells harboring the K56R mutant ribosome exhibited enhanced translational activity during the stationary phase of cell growth. In addition, the K56R mutant ribosome exhibited increased 70S complex stability in the presence of low Mg2+ concentrations. We therefore conclude that the observed increase in protein synthesis activity by the K56R mutant ribosome reflects increased stability of the 70S complex and is responsible for the increase in α-amylase production seen in the affected strain.

scholarly journals IL-23 induces regulatory T cell plasticity with implications for inflammatory skin diseases

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Arun K. Kannan ◽  
Zhi Su ◽  
Donna M. Gauvin ◽  
Stephanie E. Paulsboe ◽  
Ryan Duggan ◽  
...  
Keyword(s):  
T Cells ◽  
Mouse Model ◽  
Skin Diseases ◽  
Treg Cells ◽  
Model Systems ◽  
Cell Plasticity ◽  
Inflammatory Skin Diseases ◽  
Pro Inflammatory Cytokines

AbstractFoxp3+ regulatory T cells (Tregs) represent a major fraction of skin resident T cells. Although normally protective, Tregs have been shown to produce pro-inflammatory cytokines in human diseases, including psoriasis. A significant hurdle in the Treg field has been the identification, or development, of model systems to study this Treg plasticity. To overcome this gap, we analyzed skin resident Tregs in a mouse model of IL-23 mediated psoriasiform dermatitis. Our results demonstrate that IL-23 drove the accumulation of Tregs; including a subpopulation that co-expressed RORγt and produced IL-17A. Genesis of this population was attenuated by a RORγt inverse agonist compound and clinically relevant therapeutics. In vitro, IL-23 drove the generation of CD4+Foxp3+RORγt+IL-17A+ cells from Treg cells. Collectively, our data shows that IL-23 drives Treg plasticity by inducing a population of CD4+Foxp3+RORγt+IL-17A+ cells that could play a role in the disease pathogenesis. Through this work, we define an in vitro system and a pre-clinical in vivo mouse model that can be used to further study Treg homeostasis and plasticity in the context of psoriasis.

scholarly journals Effect of Farnesol on a Mouse Model of Systemic Candidiasis, Determined by Use of a DPP3 Knockout Mutant of Candida albicans

2007 ◽  
Vol 75 (4) ◽  
pp. 1609-1618 ◽  
Author(s):  
Dhammika H. M. L. P. Navarathna ◽  
Jacob M. Hornby ◽  
Navasona Krishnan ◽  
Anne Parkhurst ◽  
Gerald E. Duhamel ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mouse Model ◽  
Tween 80 ◽  
Sublethal Dose ◽  
Systemic Candidiasis ◽  
Knockout Mutant ◽  
Gene Encoding

ABSTRACTThis work extends our previous observation that the fungusCandida albicanssecretes micromolar levels of farnesol and that accumulation of farnesol in vitro prevents the yeast-to-mycelium conversion in a quorum-sensing manner. What does farnesol do in vivo? The purpose of this study was to determine the role of farnesol during infection with a well-established mouse model of systemic candidiasis withC. albicansA72 administered by tail vein injection. This question was addressed by altering both endogenous and exogenous farnesol. For endogenous farnesol, we created a knockout mutation inDPP3, the gene encoding a phosphatase which converts farnesyl pyrophosphate to farnesol. This mutant (KWN2) produced six times less farnesol and was ca. 4.2 times less pathogenic than its SN152 parent. The strain withDPP3reconstituted (KWN4) regained both its farnesol production levels and pathogenicity. These mutants (KWN1 to KWN4) retained their full dimorphic capability. With regard to exogenous farnesol, farnesol was administered either intraperitoneally (i.p.) or orally in the drinking water. Mice receivingC. albicansintravenously and farnesol (20 mM) orally had enhanced mortality (P< 0.03). Similarly, mice (n= 40) injected with 1.0 ml of 20 mM farnesol i.p. had enhanced mortality (P< 0.03), and the onset of mortality was 30 h sooner than for mice which received a control injection without farnesol. The effect of i.p. farnesol was more pronounced (P< 0.04) when mice were inoculated with a sublethal dose ofC. albicans. These mice started to die 4 days earlier, and the percent survival on day 6 postinoculation (p.i.) was five times lower than for mice receivingC. albicanswith control i.p. injections. In all experiments, mice administered farnesol alone or Tween 80 alone remained normal throughout a 14-day observation period. Finally, beginning at 12 h p.i., higher numbers ofC. albicanscells were detected in kidneys from mice receiving i.p. farnesol than in those from mice receiving control i.p. injections. Thus, reduced endogenous farnesol decreased virulence, while providing exogenous farnesol increased virulence. Taken together, these data suggest that farnesol may play a role in disease pathogenesis, either directly or indirectly, and thus may represent a newly identified virulence factor.

scholarly journals Roles of 3-Deoxy-d-manno-2-Octulosonic Acid Transferase from Moraxella catarrhalis in Lipooligosaccharide Biosynthesis and Virulence

2005 ◽  
Vol 73 (7) ◽  
pp. 4222-4230 ◽  
Author(s):  
Daxin Peng ◽  
Biswa P. Choudhury ◽  
Ronald S. Petralia ◽  
Russell W. Carlson ◽  
Xin-Xing Gu
Keyword(s):  
Moraxella Catarrhalis ◽  
Lipid A ◽  
Therapeutic Interventions ◽  
Core Oligosaccharide ◽  
Gene Encoding ◽  
Oligosaccharide Moiety ◽  
Normal Human ◽  
Human Infections

ABSTRACT Lipooligosaccharide (LOS), a major outer membrane component of Moraxella catarrhalis, is a possible virulence factor in the pathogenesis of human infections caused by the organism. However, information about the roles of the oligosaccharide chain from LOS in bacterial infection remains limited. Here, a kdtA gene encoding 3-deoxy-d-manno-2-octulosonic acid (Kdo) transferase, which is responsible for adding Kdo residues to the lipid A portion of the LOS, was identified by transposon mutagenesis and construction of an isogenic kdtA mutant in strain O35E. The resulting O35EkdtA mutant produced only lipid A without any core oligosaccharide, and it was viable. Physicochemical and biological analysis revealed that the mutant was susceptible to hydrophobic reagents and a hydrophilic glycopeptide and was sensitive to bactericidal activity of normal human serum. Importantly, the mutant showed decreased toxicity by the Limulus amebocyte lysate assay, reduced adherence to human epithelial cells, and enhanced clearance in lungs and nasopharynx in a mouse aerosol challenge model. These data suggest that the oligosaccharide moiety of the LOS is important for the biological activity of the LOS and the virulence capability of the bacteria in vitro and in vivo. This study may bring new insights into novel vaccines or therapeutic interventions against M. catarrhalis infections.

scholarly journals Treatment of the mouse model of mucopolysaccharidosis type IIIB with lentiviral-NAGLU vector

2005 ◽  
Vol 388 (2) ◽  
pp. 639-646 ◽  
Author(s):  
Paola Di NATALE ◽  
Carmela Di DOMENICO ◽  
Nadia GARGIULO ◽  
Sigismondo CASTALDO ◽  
Enrico GONZALEZ Y REYERO ◽  
...  
Keyword(s):  
Mouse Model ◽  
Heparan Sulphate ◽  
Autosomal Recessive Disorder ◽  
Normal Activity ◽  
Pcr Analysis ◽  
Gene Encoding ◽  
Knockout Mouse Model ◽  
Intravenous Injections

The Sanfilippo syndrome type B (mucopolysaccharidosis IIIB) is an autosomal recessive disorder due to mutations in the gene encoding NAGLU (α-N-acetylglucosaminidase), one of the enzymes required for the degradation of the GAG (glycosaminoglycan) heparan sulphate. No therapy exists for affected patients. We have shown previously the efficacy of lentiviral-NAGLU-mediated gene transfer in correcting in vitro the defect on fibroblasts of patients. In the present study, we tested the therapy in vivo on a knockout mouse model using intravenous injections. Mice (8–10 weeks old) were injected with one of the lentiviral doses through the tail vein and analysed 1 month after treatment. A single injection of lentiviral-NAGLU vector resulted in transgene expression in liver, spleen, lung and heart of treated mice, with the highest level reached in liver and spleen. Expression of 1% normal NAGLU activity in liver resulted in a 77% decrease in the GAG content; more remarkably, an expression of 0.16% normal activity in lung was capable of decreasing the GAG level by 29%. Long-term (6 months) follow up of the gene therapy revealed that the viral genome integration persisted in the target tissues, although the real-time PCR analysis showed a decrease in the vector DNA content with time. Interestingly, the decrease in GAG levels was maintained in liver, spleen, lung and heart of treated mice. These results show the promising potential and the limitations of lentiviral-NAGLU vector to deliver the human NAGLU gene in vivo.

scholarly journals The promoter of the human interleukin-2 gene contains two octamer-binding sites and is partially activated by the expression of Oct-2.

1990 ◽  
Vol 10 (10) ◽  
pp. 5464-5472 ◽  
Author(s):  
M P Kamps ◽  
L Corcoran ◽  
J H LeBowitz ◽  
D Baltimore
Keyword(s):  
T Cells ◽  
Binding Sites ◽  
Interleukin 2 ◽  
Point Mutations ◽  
Transcriptional Response ◽  
Initiation Site ◽  
Gene Encoding ◽  
Transcriptional Initiation

The gene encoding interleukin-2 (IL-2) contains a sequence 52 to 326 nucleotides upstream of its transcriptional initiation site that promotes transcription in T cells that have been activated by costimulation with tetradecanoyl phorbol myristyl acetate (TPA) and phytohemagglutinin (PHA). We found that the ubiquitous transcription factor, Oct-1, bound to two previously identified motifs within the human IL-2 enhancer, centered at nucleotides -74 and -251. Each site in the IL-2 enhancer that bound Oct-1 in vitro was also required to achieve a maximal transcriptional response to TPA plus PHA in vivo. Point mutations within either the proximal or distal octamer sequences reduced the response of the enhancer to activation by 54 and 34%, respectively. Because the murine T-cell line EL4 constitutively expresses Oct-2 and requires only TPA to induce transcription of the IL-2 gene, the effect of Oct-2 expression on activation of the IL-2 promoter in Jurkat T cells was determined. Expression of Oct-2 potentiated transcription 13-fold in response to TPA plus PHA and permitted the enhancer to respond to the single stimulus of TPA. Therefore, both the signal requirements and the magnitude of the transcription response of the IL-2 promoter can be modulated by Oct-2.

scholarly journals Gene editing preserves visual function in a mouse model of retinal degeneration

2019 ◽  
Author(s):  
Paola Vagni ◽  
Laura E. Perlini ◽  
Naïg A. L. Chenais ◽  
Tommaso Marchetti ◽  
Martina Parrini ◽  
...  
Keyword(s):  
Mouse Model ◽  
Retinitis Pigmentosa ◽  
Gene Editing ◽  
Point Mutations ◽  
Loss Of Function ◽  
Inherited Retinal Dystrophies ◽  
Retinal Dystrophies ◽  
Function Point

AbstractInherited retinal dystrophies are a large and heterogeneous group of degenerative diseases caused by mutations in various genes. Given the favourable anatomical and immunological characteristics of the eye, gene therapy holds great potential for their treatment. We used a tailored CRISPR/Cas9-based gene editing system to prevent retinal photoreceptor death in the Rd10 mouse model of retinitis pigmentosa. We tested the gene editing toolin vitroand then usedin vivosubretinal electroporation to deliver it to one of the retinas of mouse pups at different stages of photoreceptor differentiation. Three months after gene editing, the treated eye exhibited a higher visual acuity compared to the untreated eye. Moreover, we observed preservation of light-evoked responses both in explanted retinas and in the visual cortex of treated animals. Our study validates a CRISPR/Cas9-based therapy as a valuable new approach for the treatment of retinitis pigmentosa caused by autosomal recessive loss-of-function point mutations.

scholarly journals The promoter of the human interleukin-2 gene contains two octamer-binding sites and is partially activated by the expression of Oct-2

1990 ◽  
Vol 10 (10) ◽  
pp. 5464-5472
Author(s):  
M P Kamps ◽  
L Corcoran ◽  
J H LeBowitz ◽  
D Baltimore
Keyword(s):  
T Cells ◽  
Binding Sites ◽  
Interleukin 2 ◽  
Point Mutations ◽  
Transcriptional Response ◽  
Initiation Site ◽  
Gene Encoding ◽  
Transcriptional Initiation

The gene encoding interleukin-2 (IL-2) contains a sequence 52 to 326 nucleotides upstream of its transcriptional initiation site that promotes transcription in T cells that have been activated by costimulation with tetradecanoyl phorbol myristyl acetate (TPA) and phytohemagglutinin (PHA). We found that the ubiquitous transcription factor, Oct-1, bound to two previously identified motifs within the human IL-2 enhancer, centered at nucleotides -74 and -251. Each site in the IL-2 enhancer that bound Oct-1 in vitro was also required to achieve a maximal transcriptional response to TPA plus PHA in vivo. Point mutations within either the proximal or distal octamer sequences reduced the response of the enhancer to activation by 54 and 34%, respectively. Because the murine T-cell line EL4 constitutively expresses Oct-2 and requires only TPA to induce transcription of the IL-2 gene, the effect of Oct-2 expression on activation of the IL-2 promoter in Jurkat T cells was determined. Expression of Oct-2 potentiated transcription 13-fold in response to TPA plus PHA and permitted the enhancer to respond to the single stimulus of TPA. Therefore, both the signal requirements and the magnitude of the transcription response of the IL-2 promoter can be modulated by Oct-2.

Recent Patents on Anti-Cancer Potential of Helenalin

2020 ◽  
Vol 15 (2) ◽  
pp. 132-142
Author(s):  
Priyanka Kriplani ◽  
Kumar Guarve
Keyword(s):  
Synergistic Effects ◽  
Therapeutic Interventions ◽  
Active Constituent ◽  
Scientific Impact ◽  
Isolation Techniques ◽  
Anti Cancer ◽  
Prevention Of Cancer ◽  
Synthetic Derivatives

Background: Arnica montana, containing helenalin as its principal active constituent, is the most widely used plant to treat various ailments. Recent studies indicate that Arnica and helenalin provide significant health benefits, including anti-inflammatory, neuroprotective, antioxidant, cholesterol-lowering, immunomodulatory, and most important, anti-cancer properties. Objective: The objective of the present study is to overview the recent patents of Arnica and its principal constituent helenalin, including new methods of isolation, and their use in the prevention of cancer and other ailments. Methods: Current prose and patents emphasizing the anti-cancer potential of helenalin and Arnica, incorporated as anti-inflammary agents in anti-cancer preparations, have been identified and reviewed with particular emphasis on their scientific impact and novelty. Results: Helenalin has shown its anti-cancer potential to treat multiple types of tumors, both in vitro and in vivo. It has also portrayed synergistic effects when given in combination with other anti- cancer drugs or natural compounds. New purification/isolation techniques are also developing with novel helenalin formulations and its synthetic derivatives have been developed to increase its solubility and bioavailability. Conclusion: The promising anti-cancer potential of helenalin in various preclinical studies may open new avenues for therapeutic interventions in different tumors. Thus clinical trials validating its tumor suppressing and chemopreventive activities, particularly in conjunction with standard therapies, are immediately required.

scholarly journals Compensatory mechanisms in resistant Anopheles gambiae AcerKis and KdrKis neurons modulate insecticide-based mosquito control

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Stéphane Perrier ◽  
Eléonore Moreau ◽  
Caroline Deshayes ◽  
Marine El-Adouzi ◽  
Delphine Goven ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Anopheles Gambiae ◽  
Calcium Concentration ◽  
Mosquito Control ◽  
Point Mutations ◽  
Resting Membrane Potential ◽  
Compensatory Mechanisms ◽  
Pyrethroid Insecticides

AbstractIn the malaria vector Anopheles gambiae, two point mutations in the acetylcholinesterase (ace-1R) and the sodium channel (kdrR) genes confer resistance to organophosphate/carbamate and pyrethroid insecticides, respectively. The mechanisms of compensation that recover the functional alterations associated with these mutations and their role in the modulation of insecticide efficacy are unknown. Using multidisciplinary approaches adapted to neurons isolated from resistant Anopheles gambiae AcerKis and KdrKis strains together with larval bioassays, we demonstrate that nAChRs, and the intracellular calcium concentration represent the key components of an adaptation strategy ensuring neuronal functions maintenance. In AcerKis neurons, the increased effect of acetylcholine related to the reduced acetylcholinesterase activity is compensated by expressing higher density of nAChRs permeable to calcium. In KdrKis neurons, changes in the biophysical properties of the L1014F mutant sodium channel, leading to enhance overlap between activation and inactivation relationships, diminish the resting membrane potential and reduce the fraction of calcium channels available involved in acetylcholine release. Together with the lower intracellular basal calcium concentration observed, these factors increase nAChRs sensitivity to maintain the effect of low concentration of acetylcholine. These results explain the opposite effects of the insecticide clothianidin observed in AcerKis and KdrKis neurons in vitro and in vivo.

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