scholarly journals A Burkholderia cenocepacia gene encoding a non-functional tyrosine phosphatase is required for the delayed maturation of the bacteria-containing vacuoles in macrophages

Microbiology ◽  
2014 ◽  
Vol 160 (7) ◽  
pp. 1332-1345 ◽  
Author(s):  
Angel Andrade ◽  
Miguel A. Valvano
Keyword(s):  
Parental Strain ◽  
Tyrosine Phosphatase ◽  
Burkholderia Cenocepacia ◽  
Macrophage Infection ◽  
Gene Encoding ◽  
Burkholderia Multivorans ◽  
Phagosomal Maturation ◽  
Weight Protein ◽  
Delayed Maturation

Burkholderia cenocepacia infects patients with cystic fibrosis. We have previously shown that B. cenocepacia can survive in macrophages within membrane vacuoles [B. cenocepacia-containing vacuoles (BcCVs)] that preclude fusion with the lysosome. The bacterial factors involved in B. cenocepacia intracellular survival are not fully elucidated. We report here that deletion of BCAM0628, encoding a predicted low molecular weight protein tyrosine phosphatase (LMW-PTP) that is restricted to B. cenocepacia strains of the transmissible ET-12 clone, accelerates the maturation of the BcCVs. Compared to the parental strain and deletion mutants in other LMW-PTPs that are widely conserved in Burkholderia species, a greater proportion of BcCVs containing the ΔBCAM0628 mutant were targeted to the lysosome. Accelerated BcCV maturation was not due to reduced intracellular viability since ΔBCAM0628 survived and replicated in macrophages similarly to the parental strain. Therefore, BCAM0628 was referred to as dpm (delayed phagosome maturation). We provide evidence that the Dpm protein is secreted during growth in vitro and upon macrophage infection. Dpm secretion requires an N-terminal signal peptide. Heterologous expression of Dpm in Burkholderia multivorans confers to this bacterium a similar phagosomal maturation delay to that found with B. cenocepacia. We demonstrate that Dpm is an inactive phosphatase, suggesting that its contribution to phagosomal maturation arrest must be unrelated to tyrosine phosphatase activity.

scholarly journals Escherichia coliO157:H7 Lacking theqseBC-Encoded Quorum-Sensing System Outcompetes the Parental Strain in Colonization of Cattle Intestines

2014 ◽  
Vol 80 (6) ◽  
pp. 1882-1892 ◽  
Author(s):  
V. K. Sharma ◽  
T. A. Casey
Keyword(s):  
Quorum Sensing ◽  
Parental Strain ◽  
Response Regulator ◽  
Stress Hormones ◽  
Gene Encoding ◽  
Fecal Shedding ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Parental Level

ABSTRACTTheqseBC-encoded quorum-sensing system regulates the motility ofEscherichia coliO157:H7 in response to bacterial autoinducer 3 (AI-3) and the mammalian stress hormones epinephrine (E) and norepinephrine (NE). TheqseCgene encodes a sensory kinase that autophosphorylates in response to AI-3, E, or NE and subsequently phosphorylates its cognate response regulator QseB. In the absence of QseC, QseB downregulates bacterial motility and virulence in animal models. In this study, we found that 8- to 10-month-old calves orally inoculated with a mixture ofE. coliO157:H7 and its isogenicqseBCmutant showed significantly higher fecal shedding of theqseBCmutant.In vitroanalysis revealed similar growth profiles and motilities of theqseBCmutant and the parental strain in the presence or absence of NE. The magnitudes of the response to NE and expression of flagellar genesflhDandfliCwere also similar for theqseBCmutant and the parental strain. The expression ofler(a positive regulator of the locus of enterocyte effacement [LEE]), theler-regulatedespAgene, and thecsgAgene (encoding curli fimbriae) was increased in theqseBCmutant compared to the parental strain. On the other hand, growth, motility, and transcription offlhD,fliC,ler,espA, andcsgAwere significantly reduced in theqseBCmutant complemented with a plasmid-cloned copy of theqseBCgenes. Thus,in vitromotility and gene expression data indicate that the near-parental level of motility, ability to respond to NE, and enhanced expression of LEE and curli genes might in part be responsible for increased colonization and fecal shedding of theqseBCmutant in calves.

Conservation of the opcL gene encoding the peptidoglycan-associated outer-membrane lipoprotein among representatives of the Burkholderia cepacia complex

2004 ◽  
Vol 53 (5) ◽  
pp. 389-398 ◽  
Author(s):  
Maria Plesa ◽  
Abdelaziz Kholti ◽  
Karen Vermis ◽  
Peter Vandamme ◽  
Stavroula Panagea ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Burkholderia Cepacia ◽  
Sequence Data ◽  
Burkholderia Cenocepacia ◽  
Burkholderia Cepacia Complex ◽  
Gene Encoding ◽  
Burkholderia Multivorans ◽  
Outer Membrane Lipoprotein ◽  
Membrane Lipoprotein ◽  
High Degree

Members of the Burkholderia cepacia complex are Gram-negative β-proteobacteria that are classified into nine genomic species or genomovars. Some representatives of this group of bacteria, such as Burkholderia multivorans (genomovar II) and Burkholderia cenocepacia (genomovar III), are considered to be dangerous pathogens for cystic fibrosis (CF) patients because of their capacity to colonize CF lungs. The opcL gene, which encodes the peptidoglycan-associated outer-membrane lipoprotein (PAL), was detected in the genome of Burkholderia sp. LB 400 by a similarity search that was based on the sequence of the Pseudomonas aeruginosa PAL, OprL. Primers that could amplify part of opcL from B. multivorans LMG 13010T were designed. This PCR fragment was used as a probe for screening of a B. multivorans genomic bank, allowing cloning of the complete opcL gene. The complete opcL gene could be PCR-amplified from DNA from all genomovars. The sequences of these opcL genes showed a high degree of conservation (> 95 %) among different species of the B. cepacia complex. OpcL protein that was purified from B. multivorans LMG 13010T was used to generate mouse polyclonal antisera against OpcL. The OpcL protein could be produced in Escherichia coli and detected in outer-membrane fractions by Western blot. Burkholderia cells were labelled by immunofluorescence staining using antibodies against OpcL, but only after treatment with EDTA and SDS. The opcL gene could be amplified directly from the sputa of 15 CF patients who were known to be colonized by B. cepacia; sequence data derived from the amplicons identified the colonizing strains as B. cenocepacia (genomovar III, n = 14) and B. multivorans (n = 1).

scholarly journals Expression and catalytic activity of the tyrosine phosphatase PTP1C is severely impaired in motheaten and viable motheaten mice.

1993 ◽  
Vol 178 (6) ◽  
pp. 2157-2163 ◽  
Author(s):  
M Kozlowski ◽  
I Mlinaric-Rascan ◽  
G S Feng ◽  
R Shen ◽  
T Pawson ◽  
...  
Keyword(s):  
Tyrosine Phosphatase ◽  
Critical Role ◽  
Sh2 Domain ◽  
Loss Of Function ◽  
Phosphotyrosine Phosphatase ◽  
Gene Encoding ◽  
Phosphatase Domain ◽  
Sh2 Domains ◽  
Src Homology

Mutations in the gene encoding the phosphotyrosine phosphatase PTP1C, a cytoplasmic protein containing a COOH-terminal catalytic and two NH2-terminal Src homology 2 (SH2) domains, have been identified in motheaten (me) and viable motheaten (mev) mice and are associated with severe hemopoietic dysregulation. The me mutation is predicted to result in termination of the PTP1C polypeptide within the first SH2 domain, whereas the mev mutation creates an insertion or deletion in the phosphatase domain. No PTP1C RNA or protein could be detected in the hemopoietic tissues of me mice, nor could PTP1C phosphotyrosine phosphatase activity be isolated from cells homozygous for the me mutation. In contrast, mice homozygous for the less severe mev mutation expressed levels of full-length PTP1C protein comparable to those detected in wild type mice and the SH2 domains of mev PTP1C bound normally to phosphotyrosine-containing ligands in vitro. Nevertheless, the mev mutation induced a marked reduction in PTP1C activity. These observations provide strong evidence that the motheaten phenotypic results from loss-of-function mutations in the PTP1C gene and imply a critical role for PTP1C in the regulation of hemopoietic differentiation and immune function.

scholarly journals Preparation and In Vitro Evaluation of RITUXfab-Decorated Lipoplexes to Improve Delivery of siRNA Targeting C1858T PTPN22 Variant in B Lymphocytes

2021 ◽  
Vol 23 (1) ◽  
pp. 408
Author(s):  
Andrea Arena ◽  
Eugenia Belcastro ◽  
Antonella Accardo ◽  
Annamaria Sandomenico ◽  
Olivia Pagliarosi ◽  
...  
Keyword(s):  
B Lymphocytes ◽  
Tyrosine Phosphatase ◽  
Hormone Replacement ◽  
Raji Cell ◽  
Inhibitory Effect ◽  
Autoimmune Disorders ◽  
Endocrine Disorders ◽  
Gene Encoding ◽  
Autoimmune Conditions

Autoimmune endocrine disorders, such as type 1 diabetes (T1D) and thyroiditis, at present are treated with only hormone replacement therapy. This emphasizes the need to identify personalized effective immunotherapeutic strategies targeting T and B lymphocytes. Among the genetic variants associated with several autoimmune disorders, the C1858T polymorphism of the protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene, encoding for Lyp variant R620W, affects the innate and adaptive immunity. We previously exploited a novel personalized immunotherapeutic approach based on siRNA delivered by liposomes (lipoplexes) that selectively inhibit variant allele expression. In this manuscript, we improved lipoplexes carrying siRNA for variant C1858T by functionalizing them with Fab of Rituximab antibody (RituxFab-Lipoplex) to specifically target B lymphocytes in autoimmune conditions, such as T1D. RituxFab-Lipoplexes specifically bind to B lymphocytes of the human Raji cell line and of human PBMC of healthy donors. RituxFab-Lipoplexes have impact on the function of B lymphocytes of T1D patients upon CpG stimulation showing a higher inhibitory effect on total cell proliferation and IgM+ plasma cell differentiation than the not functionalized ones. These results might open new pathways of applicability of RituxFab-Lipoplexes, such as personalized immunotherapy, to other autoimmune disorders, where B lymphocytes are the prevalent pathogenic immunocytes.

1742-P: Targeting the Low Molecular Weight Protein Tyrosine Phosphatase for Obesity-Associated Diabetes Therapy

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 1742-P
Author(s):  
STEPHANIE M. STANFORD ◽  
MICHAEL A. DIAZ ◽  
JIWEN J. ZOU ◽  
ROBERT J. ARDECKY ◽  
ANTHONY PINKERTON ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Low Molecular Weight ◽  
Molecular Weight Protein ◽  
Diabetes Therapy ◽  
Protein Tyrosine ◽  
Weight Protein ◽  
Low Molecular Weight Protein

In Vitro, In Silico and Ex Vivo Studies of Dihydroartemisinin Derivatives as Antitubercular Agents

2019 ◽  
Vol 19 (8) ◽  
pp. 633-644 ◽  
Author(s):  
Komal Kalani ◽  
Sarfaraz Alam ◽  
Vinita Chaturvedi ◽  
Shyam Singh ◽  
Feroz Khan ◽  
...  
Keyword(s):  
Bone Marrow ◽  
In Silico ◽  
Ex Vivo ◽  
Virulent Strain ◽  
Infection Model ◽  
Mouse Bone Marrow ◽  
Significant Activity ◽  
Macrophage Infection ◽  
In Silico Studies

Introduction: As a part of our drug discovery program for anti-tubercular agents, dihydroartemisinin (DHA-1) was screened against Mtb H37Rv, which showed moderate anti-tubercular activity (>25.0 µg/mL). These results prompted us to carry out the chemical transformation of DHA-1 into various derivatives and study their antitubercular potential. Materials and Methods: DHA-1 was semi-synthetically converted into four new acyl derivatives (DHA-1A – DHA-1D) and in-vitro evaluated for their anti-tubercular potential against Mycobacterium tuberculosis H37Rv virulent strain. The derivatives, DHA-1C (12-O-(4-nitro) benzoyl; MIC 12.5 µg/mL) and DHA-1D (12-O-chloro acetyl; MIC 3.12µg/mL) showed significant activity against the pathogen. Results: In silico studies of the most active derivative (DHA-1D) showed interaction with ARG448 inhibiting the mycobacterium enzymes. Additionally, it showed no cytotoxicity towards the Vero C1008 cells and Mouse bone marrow derived macrophages. Conclusion: DHA-1D killed 62% intracellular M. tuberculosis in Mouse bone marrow macrophage infection model. To the best of our knowledge, this is the first-ever report on the antitubercular potential of dihydroartemisinin and its derivatives. Since dihydroartemisinin is widely used as an antimalarial drug; these results may be of great help in anti-tubercular drug development from a very common, inexpensive, and non-toxic natural product.

Isolation and Identification of a Potent PTP1B Inhibitor, Ursolic Acid, from Carolina Jasmine (Gelsemium sempervirens (L.) J.St.-Hil.)

2020 ◽  
Vol 17 (12) ◽  
pp. 939-943
Author(s):  
Toshiro Noshita ◽  
Yusuke Kakizoe ◽  
Satoshi Tanabe ◽  
Hidekazu Ouchi ◽  
Akihiro Tai
Keyword(s):  
Ursolic Acid ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Active Agent ◽  
Protein Tyrosine Phosphatase 1B ◽  
Inhibiting Activity ◽  
Inhibition Activity ◽  
Isolation And Identification ◽  
Gelsemium Sempervirens

Extracts of Carolina jasmine (Gelsemium sempervirens (L.) J.St.-Hil.) petals were evaluated in vitro for inhibition activity against protein tyrosine phosphatase 1B (PTP1B). The principle active agent was also isolated from the extract and identified as ursolic acid (1). This is the first report of ursolic acid from G. sempervirens and of PTP1B-inhibiting activity in the genus Gelsemium.

scholarly journals PTPRD-inactivation-induced CXCL8 promotes angiogenesis and metastasis in gastric cancer and is inhibited by metformin

2019 ◽  
Vol 38 (1) ◽  
Author(s):  
Won Jung Bae ◽  
Ji Mi Ahn ◽  
Hye Eun Byeon ◽  
Seokwhi Kim ◽  
Dakeun Lee
Keyword(s):  
Microarray Analysis ◽  
Protein Tyrosine Phosphatase ◽  
Cancer Metastasis ◽  
Tyrosine Phosphatase ◽  
Underlying Mechanism ◽  
Tube Formation ◽  
Potential Therapeutic Target ◽  
Efficient Treatment ◽  
Stat3 Signaling

Abstract Background Protein tyrosine phosphatase receptor delta (PTPRD) is frequently inactivated in various types of cancers. Here, we explored the underlying mechanism of PTPRD-loss-induced cancer metastasis and investigated an efficient treatment option for PTPRD-inactivated gastric cancers (GCs). Methods PTPRD expression was evaluated by immunohistochemistry. Microarray analysis was used to identify differentially expressed genes in PTPRD-inactivated cancer cells. Quantitative reverse transcription (qRT-PCR), western blotting, and/or enzyme-linked immunosorbent assays were used to investigate the PTPRD-CXCL8 axis and the expression of other related genes. An in vitro tube formation assay was performed using HUVECs. The efficacy of metformin was assessed by MTS assay. Results PTPRD was frequently downregulated in GCs and the loss of PTPRD expression was associated with advanced stage, worse overall survival, and a higher risk of distant metastasis. Microarray analysis revealed a significant increase in CXCL8 expression upon loss of PTPRD. This was validated in various GC cell lines using transient and stable PTPRD knockdown. PTPRD-loss-induced angiogenesis was mediated by CXCL8, and the increase in CXCL8 expression was mediated by both ERK and STAT3 signaling. Thus, specific inhibitors targeting ERK or STAT3 abrogated the corresponding signaling nodes and inhibited PTPRD-loss-induced angiogenesis. Additionally, metformin was found to efficiently inhibit PTPRD-loss-induced angiogenesis, decrease cell viability in PTPRD-inactivated cancers, and reverse the decrease in PTPRD expression. Conclusions Thus, the PTPRD-CXCL8 axis may serve as a potential therapeutic target, particularly for the suppression of metastasis in PTPRD-inactivated GCs. Hence, we propose that the therapeutic efficacy of metformin in PTPRD-inactivated cancers should be further investigated.

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