scholarly journals Collectin Kidney 1 Plays an Important Role in Innate Immunity against Streptococcus pneumoniae Infection

2017 ◽  
Vol 9 (2) ◽  
pp. 217-228 ◽  
Author(s):  
Insu Hwang ◽  
Kenichiro Mori ◽  
Katsuki Ohtani ◽  
Yasuyuki Matsuda ◽  
Nitai Roy ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Streptococcus Pneumoniae ◽  
Pulmonary Inflammation ◽  
Dependent Manner ◽  
Complement Pathway ◽  
Calcium Dependent ◽  
Host Protection ◽  
In The Wild

Collectins are C-type lectins that are involved in innate immunity as pattern recognition molecules. Recently, collectin kidney 1 (CL-K1) has been discovered, and in vitro studies have shown that CL-K1 binds to microbes and activates the lectin complement pathway. However, in vivo functions of CL-K1 against microbes have not been elucidated. To investigate the biological functions of CL-K1, we generated CL-K1 knockout (CL-K1-/-) mice and then performed a Streptococcus pneumoniae infection analysis. First, we found that recombinant human CL-K1 bound to S. pneumoniae in a calcium-dependent manner, and induced complement activation. CL-K1-/- mice sera formed less C3 deposition on S. pneumoniae. Furthermore, immunofluorescence analysis in the wild-type (WT) mice demonstrated that CL-K1 and C3 were localized on S. pneumoniae in infected lungs. CL-K1-/- mice revealed decreased phagocytosis of S. pneumoniae. Consequently, less S. pneumoniae clearance was observed in their lungs. CL-K1-/- mice showed severe pulmonary inflammation and weight loss in comparison with WT mice. Finally, the decreased clearance and severe pulmonary inflammation caused by S. pneumoniae infection might cause higher CL-K1-/- mice lethality. Our results suggest that CL-K1 might play an important role in host protection against S. pneumoniae infection through the activation of the lectin complement pathway.

Reticulon 3-mediated Chk2/p53 activation suppresses hepatocellular carcinogenesis and is blocked by hepatitis B virus

Gut ◽  
2020 ◽  
pp. gutjnl-2020-321386
Author(s):  
Shushu Song ◽  
Yinghong Shi ◽  
Weicheng Wu ◽  
Hao Wu ◽  
Lei Chang ◽  
...  
Keyword(s):  
Cellular Proliferation ◽  
Dependent Manner ◽  
Mice Model ◽  
Calcium Dependent ◽  
B Virus ◽  
P53 Activation ◽  
Underlying Mechanisms ◽  
Induced Apoptosis

ObjectiveDysfunction of endoplasmic reticulum (ER) proteins is closely related to homeostasis disturbance and malignant transformation of hepatocellular carcinoma (HCC). Reticulons (RTN) are a family of ER-resident proteins critical for maintaining ER function. Nevertheless, the precise roles of RTN in HCC remain largely unclear. The aim of the study is to examine the effect of reticulon family member RTN3 on HCC development and explore the underlying mechanisms.DesignClinical HCC samples were collected to assess the relationship between RTN3 expression and patients’ outcome. HCC cell lines were employed to examine the effects of RTN3 on cellular proliferation, apoptosis and signal transduction in vitro. Nude mice model was used to detect the role of RTN3 in modulating tumour growth in vivo.ResultsWe found that RTN3 was highly expressed in normal hepatocytes but frequently downregulated in HCC. Low RTN3 expression predicted poor outcome in patients with HCC in TP53 gene mutation and HBV infection status-dependent manner. RTN3 restrained HCC growth and induced apoptosis by activating p53. Mechanism studies indicated that RTN3 facilitated p53 Ser392 phosphorylation via Chk2 and enhanced subsequent p53 nuclear localisation. RTN3 interacted with Chk2, recruited it to ER and promoted its activation in an ER calcium-dependent manner. Nevertheless, the tumour suppressive effects of RTN3 were abrogated in HBV-positive cells. HBV surface antigen competed with Chk2 for RTN3 binding and blocked RTN3-mediated Chk2/p53 activation.ConclusionThe findings suggest that RTN3 functions as a novel suppressor of HCC by activating Chk2/p53 pathway and provide more clues to better understand the oncogenic effects of HBV.

scholarly journals Annexin VI: an intracellular target for ATP.

1999 ◽  
Vol 46 (3) ◽  
pp. 801-812 ◽  
Author(s):  
J Bandorowicz-Pikuła ◽  
M Danieluk ◽  
A Wrzosek ◽  
R Buś ◽  
R Buchet ◽  
...  
Keyword(s):  
Nucleotide Binding ◽  
Dependent Manner ◽  
Amino Acid Residues ◽  
Binding Motifs ◽  
Calcium Dependent ◽  
Annexin Vi ◽  
Self Association ◽  
Nucleotide Binding Proteins

Annexin VI (AnxVI), an Ca2+- and phospholipid-binding protein, interacts in vitro with ATP in a calcium-dependent manner. Experimental evidence indicates that its nucleotide-binding domain which is localized in the C-terminal half of the protein differs structurally from ATP/GTP-binding motifs found in other nucleotide-binding proteins. The amino-acid residues of AnxVI directly involved in ATP binding have not been yet defined. Binding of ATP to AnxVI induces changes in the secondary and tertiary structures of protein, affecting the affinity of AnxVI for Ca2+ and, in consequence, influencing the Ca2+-dependent activities of AnxVI: binding to F-actin and to membranous phospholipids, and self-association of the annexin molecules. These observations suggest that ATP is a functional ligand for AnxVI in vivo, and ATP-sensitive AnxVI may play the role of a factor coupling vesicular transport and calcium homeostasis to cellular metabolism.

scholarly journals OmpR phosphorylation regulates ompS1 expression by differentially controlling the use of promoters

Microbiology ◽  
2014 ◽  
Vol 160 (4) ◽  
pp. 733-741 ◽  
Author(s):  
Mario Alberto Flores-Valdez ◽  
Marcos Fernández-Mora ◽  
Miguel Ángel Ares ◽  
Jorge A. Girón ◽  
Edmundo Calva ◽  
...  
Keyword(s):  
Regulatory Sequence ◽  
Dependent Manner ◽  
In The Wild ◽  
P2 Promoter ◽  
Regulatory Effects ◽  
Encoding Genes ◽  
Effect Of Glucose

The Salmonella enterica ompS1 gene encodes a quiescent porin that belongs to the OmpC/OmpF family. In the present work we analysed the regulatory effects of OmpR phosphorylation on ompS1 expression. We found that in vivo, OmpR in its phosphorylated form (OmpR-P) was important in the regulation of the two ompS1 promoters: OmpR-P activated the P1 promoter and repressed the P2 promoter in an EnvZ-dependent manner; expression occurs from the P2 promoter in an ompR mutant. In vitro, OmpR-P had a higher DNA-binding-affinity to the ompS1 promoter region than OmpR and OmpRD55A, showing an affinity even higher than that of equivalent DNA regions in the 5′-upstream regulatory sequence of the major porin-encoding genes ompC and ompF. By analysing different environmental conditions, we found that glucose and glycerol enhanced ompS1 expression in the wild-type strain. Interestingly the stimulation by glycerol was OmpR-dependent while the effect of glucose was still observed in the absence of OmpR. Acetyl phosphate produced by the AckA-Pta pathway did not influence ompS1 regulation. These data indicate the important role of the phosphorylation in the activity of OmpR on the differential regulation of both ompS1 promoters and its impact on the pathogenesis.

In vitro and in vivo roles in Collectin Kidney 1 (CL-K1) with innate immunity against Streptococcus pneumoniae

Immunobiology ◽  
2016 ◽  
Vol 221 (10) ◽  
pp. 1217 ◽  
Author(s):  
Insu Hwang ◽  
Kenichiro Mori ◽  
Katsuki Ohtani ◽  
Yasuyuki Matsuda ◽  
Nitai Roy ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Streptococcus Pneumoniae

scholarly journals Demonstration of N , N -Dimethyldithiocarbamate as a Copper-Dependent Antibiotic against Multiple Upper Respiratory Tract Pathogens

2021 ◽  
Author(s):  
Sanjay V. Menghani ◽  
Angela Rivera ◽  
Miranda Neubert ◽  
James R. Hagerty ◽  
Lourdes Lewis ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Streptococcus Pneumoniae ◽  
Respiratory Tract ◽  
Dependent Manner ◽  
Upper Respiratory Tract ◽  
Coccidioides Posadasii ◽  
Content Type ◽  
Upper Respiratory

With the rise of antibiotic resistance, approaches that add new antimicrobials to the current repertoire are vital. Here, we investigate putative and known copper ionophores in an attempt to intoxicate bacteria and use ionophore/copper synergy, and we ultimately find success with N , N -dimethyldithiocarbamate (DMDC). We show that DMDC has in vitro efficacy in a copper-dependent manner and kills pathogens across three different kingdoms, Streptococcus pneumoniae ( Sr. pneumoniae ), Coccidioides posadasii , and Schistosoma mansoni , and in vivo efficacy against Sr . pneumoniae .

scholarly journals Dual oxidase 1 promotes antiviral innate immunity

2021 ◽  
Vol 118 (26) ◽  
pp. e2017130118
Author(s):  
Demba Sarr ◽  
Aaron D. Gingerich ◽  
Nuha Milad Asthiwi ◽  
Faris Almutairi ◽  
Giuseppe A. Sautto ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Influenza Virus ◽  
Epithelial Cells ◽  
Host Cells ◽  
Dependent Manner ◽  
Dual Oxidase ◽  
Antiviral Innate Immunity

Dual oxidase 1 (DUOX1) is an NADPH oxidase that is highly expre-ssed in respiratory epithelial cells and produces H2O2 in the airway lumen. While a line of prior in vitro observations suggested that DUOX1 works in partnership with an airway peroxidase, lactoperoxidase (LPO), to produce antimicrobial hypothiocyanite (OSCN−) in the airways, the in vivo role of DUOX1 in mammalian organisms has remained unproven to date. Here, we show that Duox1 promotes antiviral innate immunity in vivo. Upon influenza airway challenge, Duox1−/− mice have enhanced mortality, morbidity, and impaired lung viral clearance. Duox1 increases the airway levels of several cytokines (IL-1β, IL-2, CCL1, CCL3, CCL11, CCL19, CCL20, CCL27, CXCL5, and CXCL11), contributes to innate immune cell recruitment, and affects epithelial apoptosis in the airways. In primary human tracheobronchial epithelial cells, OSCN− is generated by LPO using DUOX1-derived H2O2 and inactivates several influenza strains in vitro. We also show that OSCN− diminishes influenza replication and viral RNA synthesis in infected host cells that is inhibited by the H2O2 scavenger catalase. Binding of the influenza virus to host cells and viral entry are both reduced by OSCN− in an H2O2-dependent manner in vitro. OSCN− does not affect the neuraminidase activity or morphology of the influenza virus. Overall, this antiviral function of Duox1 identifies an in vivo role of this gene, defines the steps in the infection cycle targeted by OSCN−, and proposes that boosting this mechanism in vivo can have therapeutic potential in treating viral infections.

scholarly journals The effects of e-cigarette vapor exposure on the transcriptome and virulence of Streptococcus pneumoniae

2019 ◽  
Author(s):  
Kamal Bagale ◽  
Santosh Paudel ◽  
Hayden Cagle ◽  
Erin Sigel ◽  
Ritwij Kulkarni
Keyword(s):  
Streptococcus Pneumoniae ◽  
Stress Response ◽  
Mouse Model ◽  
Pathogenic Bacteria ◽  
Sugar Transport ◽  
Dependent Manner ◽  
Altered Expression ◽  
Acute Pneumonia

AbstractThe effects of e-cigarette vapor (EV) exposure on the physiology of respiratory microflora are not fully defined. We analyzed the effects of exposure to vapor from nicotine-containing and nicotine-free e-liquid formulations on virulence and transcriptome of Streptococcus pneumoniae strain TIGR4, a pathogen that asymptomatically colonizes human nasopharyngeal mucosa. TIGR4 was pre-exposed for 2h to nicotine-containing EV extract (EVE+NIC), nicotine-free EV extract (EVE−NIC), cigarette smoke extract (CSE), or nutrient-rich TS broth (control). The differences in the treatment and control TIGR4 were explored using transcriptome sequencing, in vitro virulence assays, and in vivo mouse model of acute pneumonia. The analysis of RNASeq profiles revealed modest changes in the expression of 14 genes involved in sugar transport and metabolism in EVE−NIC pre-exposed TIGR4 compared to the control. While, EVE+NIC or CSE exposure altered expression of 264 and 982 genes, respectively, most of which were involved in metabolism and stress response. Infection in a mouse model of acute pneumonia with control TIGR4 or with TIGR4 pre-exposed to EVE+NIC, EVE−NIC, or CSE did not show significant differences in disease parameters, such as bacterial organ burden and respiratory cytokine response. Interestingly, TIGR4 exposed to CSE or EVE+NIC (but not EVE−NIC) exhibited moderate induction of biofilm formation. However, none of the treatment groups showed significant alterations in pneumococcal hydrophobicity or epithelial cell adherence. In summary, our study reports that exposure to EV significantly alters the S. pneumoniae transcriptome in a nicotine-dependent manner without affecting pneumococcal virulence.ImportanceWith the increasing popularity of e-cigarettes amongst cigarette smoking and non-smoking adults and children, and the recent reports of vaping related lung illnesses and deaths, further analysis of the adverse health effects of e-cigarette vapor (EV) exposure is warranted. Since pathogenic bacteria such as Streptococcus pneumoniae can colonize the human nasopharynx as commensals, they may be affected by the exposure to bioactive chemicals in EV. Hence in this study we examined the effects of EV exposure on the physiology of S. pneumoniae strain TIGR4. In order to differentiate between the effects of nicotine and non-nicotine components, we specifically compared RNASeq profiles and virulence of TIGR4 exposed to vapor from nicotine-containing and nicotine-free e-liquid formulations. We observed that nicotine-containing EV augmented TIGR4 biofilms and altered expression of TIGR4 genes predominantly involved in metabolism and stress response. However, neither nicotine-containing nor nicotine-free EV affected TIGR4 virulence in a mouse model.

scholarly journals IQD proteins integrate auxin and calcium signaling to regulate microtubule dynamics during Arabidopsis development

2018 ◽  
Author(s):  
Jos R. Wendrich ◽  
Bao-Jun Yang ◽  
Pieter Mijnhout ◽  
Hong-Wei Xue ◽  
Bert De Rybel ◽  
...  
Keyword(s):  
Calcium Signaling ◽  
Binding Proteins ◽  
Preprophase Band ◽  
Auxin Signaling ◽  
Dependent Manner ◽  
Regulatory Pathways ◽  
Calcium Dependent ◽  
Specific Effects

AbstractGeometry and growth and division direction of individual cells are major contributors to plant organ shape and these processes are dependent on dynamics of microtubules (MT). Different MT structures, like the cortical microtubules, preprophase band and mitotic spindle, are characterized by diverse architectural dynamics (Hashimoto, 2015). While several MT binding proteins have been identified that have various effects on MT stability and architecture, they do not discriminate between the different MT structures. It is therefore likely that specific MT binding proteins exist that differentiate between MT structures in order to allow for the differences in architectural dynamics. Although evidence for the effect of specific cues, such as light and auxin, on MT dynamics has been shown in recent years (Lindeboom et al., 2013; Chen et al., 2014), it remains unknown how such cues are integrated and lead to specific effects. Here we provide evidence for how auxin and calcium signaling can be integrated to modulate MT dynamics, by means of IQD proteins. We show that the Arabidopsis IQD15-18 subclade of this family is regulated by auxin signaling, can bind calmodulins in a calcium-dependent manner and are evolutionarily conserved. Furthermore, AtIQD15-18 directly bind SPIRAL2 protein in vitro and in vivo and modulate its function, likely in a calmodulin-dependent way, thereby providing a missing link between two important regulatory pathways of MT dynamics.One sentence summaryIQD proteins integrate auxin and calcium signaling, two major signaling pathways, to control the cytoskeleton dynamics and cell shape of Arabidopsis.

scholarly journals Essential role of CIB1 in regulating PAK1 activation and cell migration

2005 ◽  
Vol 170 (3) ◽  
pp. 465-476 ◽  
Author(s):  
Tina M. Leisner ◽  
Mingjuan Liu ◽  
Zahara M. Jaffer ◽  
Jonathan Chernoff ◽  
Leslie V. Parise
Keyword(s):  
Cell Migration ◽  
Specific Interaction ◽  
Dependent Manner ◽  
Lim Kinase ◽  
Calcium Dependent ◽  
Cellular Processes ◽  
Cofilin Phosphorylation ◽  
Pak1 Activation

p21-activated kinases (PAKs) regulate many cellular processes, including cytoskeletal rearrangement and cell migration. In this study, we report a direct and specific interaction of PAK1 with a 22-kD Ca2+-binding protein, CIB1, which results in PAK1 activation both in vitro and in vivo. CIB1 binds to PAK1 within discrete regions surrounding the inhibitory switch domain in a calcium-dependent manner, providing a potential mechanism of CIB1-induced PAK1 activation. CIB1 overexpression significantly decreases cell migration on fibronectin as a result of a PAK1-and LIM kinase–dependent increase in cofilin phosphorylation. Conversely, the RNA interference–mediated depletion of CIB1 increases cell migration and reduces normal adhesion-induced PAK1 activation and cofilin phosphorylation. Together, these results demonstrate that endogenous CIB1 is required for regulated adhesion-induced PAK1 activation and preferentially induces a PAK1-dependent pathway that can negatively regulate cell migration. These results point to CIB1 as a key regulator of PAK1 activation and signaling.

scholarly journals Flagellar Radial Spoke Protein 2 Is a Calmodulin Binding Protein Required for Motility in Chlamydomonas reinhardtii

2004 ◽  
Vol 3 (1) ◽  
pp. 72-81 ◽  
Author(s):  
Pinfen Yang ◽  
Chun Yang ◽  
Winfield S. Sale
Keyword(s):  
Calcium Binding ◽  
Regulatory Subunit ◽  
Dependent Manner ◽  
Radial Spoke ◽  
Calcium Dependent ◽  
Calmodulin Binding ◽  
Morphological Studies ◽  
Radial Spokes

ABSTRACT Genetic and morphological studies have revealed that the radial spokes regulate ciliary and flagellar bending. Functional and biochemical analysis and the discovery of calmodulin in the radial spokes suggest that the regulatory mechanism involves control of axonemal protein phosphorylation and calcium binding to spoke proteins. To identify potential regulatory proteins in the radial spoke, in-gel kinase assays were performed on isolated axonemes and radial spoke fractions. The results indicated that radial spoke protein 2 (RSP2) can bind ATP and transfer phosphate in vitro. RSP2 was cloned and mapped to the PF24 locus, a gene required for motility. Sequencing revealed that pf24 contains a point mutation converting the first ATG to ATA, resulting in only trace amounts of RSP2 and confirming the RSP2 mapping. Surprisingly, the sequence does not include signature domains for conventional kinases, indicating that RSP2 may not perform as a protein kinase in vivo. However, the predicted RSP2 protein sequence contains Ca2+-dependent calmodulin binding motifs and a GAF domain, a domain found in diverse signaling proteins for binding small ligands including cyclic nucleotides. As predicted from the sequence, recombinant RSP2 binds calmodulin in a calcium-dependent manner. We postulate that RSP2 is a regulatory subunit of the radial spoke involved in localization of calmodulin for control of motility.

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