scholarly journals Small Noncoding RNA CjNC110 Influences Motility, Autoagglutination, AI-2 Localization, Hydrogen Peroxide Sensitivity, and Chicken Colonization in Campylobacter jejuni

2020 ◽  
Vol 88 (7) ◽  
Author(s):  
Amanda J. Kreuder ◽  
Brandon Ruddell ◽  
Kathy Mou ◽  
Alan Hassall ◽  
Qijing Zhang ◽  
...  

ABSTRACT Small noncoding RNAs (ncRNAs) are involved in many important physiological functions in pathogenic microorganisms. Previous studies have identified the presence of noncoding RNAs in the major zoonotic pathogen Campylobacter jejuni; however, few have been functionally characterized to date. CjNC110 is a conserved ncRNA in C. jejuni, located downstream of the luxS gene, which is responsible for the production of the quorum sensing molecule autoinducer-2 (AI-2). In this study, we utilized strand specific high-throughput RNAseq to identify potential targets or interactive partners of CjNC110 in a sheep abortion clone of C. jejuni. These data were then utilized to focus further phenotypic evaluation of the role of CjNC110 in motility, autoagglutination, quorum sensing, hydrogen peroxide sensitivity, and chicken colonization in C. jejuni. Inactivation of the CjNC110 ncRNA led to a statistically significant decrease in autoagglutination ability as well as increased motility and hydrogen peroxide sensitivity compared to the wild-type. Extracellular AI-2 detection was decreased in ΔCjNC110; however, intracellular AI-2 accumulation was significantly increased, suggesting a key role of CjNC110 in modulating the transport of AI-2. Notably, ΔCjNC110 also showed a decreased ability to colonize chickens. Complementation of CjNC110 restored all phenotypic changes back to wild-type levels. The collective results of the phenotypic and transcriptomic changes observed in our data provide valuable insights into the pathobiology of C. jejuni sheep abortion clone and strongly suggest that CjNC110 plays an important role in the regulation of energy taxis, flagellar glycosylation, cellular communication via quorum sensing, oxidative stress tolerance, and chicken colonization in this important zoonotic pathogen.

2020 ◽  
Author(s):  
Amanda J. Kreuder ◽  
Brandon Ruddell ◽  
Kathy Mou ◽  
Alan Hassall ◽  
Qijing Zhang ◽  
...  

ABSTRACTSmall non-coding RNAs are involved in many important physiological functions in pathogenic microorganisms. Previous studies have identified the presence of non-coding RNAs in the major zoonotic pathogen Campylobacter jejuni, however, few have been functionally characterized to date. CjNC110 is a conserved ncRNA in C. jejuni, located downstream of the luxS gene which is responsible for the production of the quorum-sensing molecule autoinducer-2 (AI-2). In this study, we utilized strand specific high-throughput RNAseq to identify potential targets or interactive partners of CjNC110 in a sheep abortion clone of C. jejuni. This data was then utilized to focus further phenotypic evaluation of the role of CjNC110 in motility, autoagglutination, quorum sensing, hydrogen peroxide sensitivity and chicken colonization in C. jejuni. Inactivation of the CjNC110 ncRNA led to a statistically significant decrease in autoagglutination ability as well as increased motility and hydrogen peroxide sensitivity when compared to wild-type. Extracellular AI-2 detection was decreased in ΔCjNC110, however, intracellular AI-2 accumulation was significantly increased, suggesting a key role of CjNC110 in modulating the transport of AI-2. Notably, ΔCjNC110 also showed a decreased ability to colonize chickens. Complementation of CjNC110 restored all phenotypic changes back to wild-type levels. The collective results of the phenotypic and transcriptomic changes observed in our data provide valuable insights into the pathobiology of C. jejuni sheep abortion clone and strongly suggest that CjNC110 plays an important role in regulation of energy taxis, flagellar glycosylation, cellular communication via quorum sensing, oxidative stress tolerance and chicken colonization in this important zoonotic pathogen.


2020 ◽  
Vol 202 (7) ◽  
Author(s):  
Ritam Sinha ◽  
Rhiannon M. LeVeque ◽  
Marvin Q. Bowlin ◽  
Michael J. Gray ◽  
Victor J. DiRita

ABSTRACT Campylobacter jejuni causes acute gastroenteritis worldwide and is transmitted primarily through poultry, in which it is often a commensal member of the intestinal microbiota. Previous transcriptome sequencing (RNA-Seq) experiment showed that transcripts from an operon encoding a high-affinity phosphate transporter (PstSCAB) of C. jejuni were among the most abundant when the bacterium was grown in chickens. Elevated levels of the pstSCAB mRNA were also identified in an RNA-Seq experiment from human infection studies. In this study, we explore the role of PstSCAB in the biology and colonization potential of C. jejuni. Our results demonstrate that cells lacking PstSCAB survive poorly in stationary phase, in nutrient-limiting media, and under osmotic conditions reflective of those in the chicken. Polyphosphate levels in the mutant cells were elevated at stationary phase, consistent with alterations in expression of polyphosphate metabolism genes. The mutant strain was highly attenuated for colonization of newly hatched chicks, with levels of bacteria at several orders of magnitude below wild-type levels. Mutant and wild type grew similarly in complex media, but the pstS::kan mutant exhibited a significant growth defect in minimal medium supplemented with l-lactate, postulated as a carbon source in vivo. Poor growth in lactate correlated with diminished expression of acetogenesis pathway genes previously demonstrated as important for colonizing chickens. The phosphate transport system is thus essential for diverse aspects of C. jejuni physiology and in vivo fitness and survival. IMPORTANCE Campylobacter jejuni causes millions of human gastrointestinal infections annually, with poultry a major source of infection. Due to the emergence of multidrug resistance in C. jejuni, there is need to identify alternative ways to control this pathogen. Genes encoding the high-affinity phosphate transporter PstSCAB are highly expressed by C. jejuni in chickens and humans. In this study, we address the role of PstSCAB on chicken colonization and other C. jejuni phenotypes. PstSCAB is required for colonization in chicken, metabolism and survival under different stress responses, and during growth on lactate, a potential growth substrate in chickens. Our study highlights that PstSCAB may be an effective target to develop mechanisms for controlling bacterial burden in both chicken and human.


2015 ◽  
Vol 83 (6) ◽  
pp. 2430-2442 ◽  
Author(s):  
Jorge E. Vidal ◽  
Joshua R. Shak ◽  
Adrian Canizalez-Roman

Clostridium perfringensstrains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by theC. perfringensAgr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. AlthoughC. perfringensstrains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrBmutant strains were not able to produce biofilms, a ΔluxSmutant produced wild-type levels. The transcript levels of CpAL-regulatedcpaandpfoAgenes, but notcpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpaand ΔpfoAmutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpbmade wild-type levels. Biofilm formation was restored in complemented Δcpa/cpaand ΔpfoA/pfoAstrains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation inC. perfringensby increasing levels of certain toxins required to build biofilms.


mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Leonardo Silva de Araujo ◽  
Marcelo Ribeiro-Alves ◽  
Thyago Leal-Calvo ◽  
Janaína Leung ◽  
Verónica Durán ◽  
...  

ABSTRACT In tuberculosis (TB), as in other infectious diseases, studies of small noncoding RNAs (sncRNA) in peripheral blood have focused on microRNAs (miRNAs) but have neglected the other major sncRNA classes in spite of their potential functions in host gene regulation. Using RNA sequencing of whole blood, we have therefore determined expression of miRNA, PIWI-interacting RNA (piRNA), small nucleolar RNA (snoRNA), and small nuclear RNA (snRNA) in patients with TB (n = 8), latent TB infection (LTBI; n = 21), and treated LTBI (LTBItt; n = 6) and in uninfected exposed controls (ExC; n = 14). As expected, sncRNA reprogramming was greater in TB than in LTBI, with the greatest changes seen in miRNA populations. However, substantial dynamics were also evident in piRNA and snoRNA populations. One miRNA and 2 piRNAs were identified as moderately accurate (area under the curve [AUC] = 0.70 to 0.74) biomarkers for LTBI, as were 1 miRNA, 1 piRNA, and 2 snoRNAs (AUC = 0.79 to 0.91) for accomplished LTBI treatment. Logistic regression identified the combination of 4 sncRNA (let-7a-5p, miR-589-5p, miR-196b-5p, and SNORD104) as a highly sensitive (100%) classifier to discriminate TB from all non-TB groups. Notably, it reclassified 8 presumed LTBI cases as TB cases, 5 of which turned out to have features of Mycobacterium tuberculosis infection on chest radiographs. SNORD104 expression decreased during M. tuberculosis infection of primary human peripheral blood mononuclear cells (PBMC) and M2-like (P = 0.03) but not M1-like (P = 0.31) macrophages, suggesting that its downregulation in peripheral blood in TB is biologically relevant. Taken together, the results demonstrate that snoRNA and piRNA should be considered in addition to miRNA as biomarkers and pathogenesis factors in the various stages of TB. IMPORTANCE Tuberculosis is the infectious disease with the worldwide largest disease burden and there remains a great need for better diagnostic biomarkers to detect latent and active M. tuberculosis infection. RNA molecules hold great promise in this regard, as their levels of expression may differ considerably between infected and uninfected subjects. We have measured expression changes in the four major classes of small noncoding RNAs in blood samples from patients with different stages of TB infection. We found that, in addition to miRNAs (which are known to be highly regulated in blood cells from TB patients), expression of piRNA and snoRNA is greatly altered in both latent and active TB, yielding promising biomarkers. Even though the functions of many sncRNA other than miRNA are still poorly understood, our results strongly suggest that at least piRNA and snoRNA populations may represent hitherto underappreciated players in the different stages of TB infection.


2011 ◽  
Vol 80 (2) ◽  
pp. 585-593 ◽  
Author(s):  
Paul Plummer ◽  
Orhan Sahin ◽  
Eric Burrough ◽  
Rachel Sippy ◽  
Kathy Mou ◽  
...  

ABSTRACTPrevious studies onCampylobacter jejunihave demonstrated the role of LuxS in motility, cytolethal distending toxin production, agglutination, and intestinal colonization; however, its direct involvement in virulence has not been reported. In this study, we demonstrate a direct role ofluxSin the virulence ofC. jejuniin two different animal hosts. The IA3902 strain, a highly virulent sheep abortion strain recently described by our laboratory, along with its isogenicluxSmutant andluxScomplement strains, was inoculated by the oral route into both a pregnant guinea pig virulence model and a chicken colonization model. In both cases, the IA3902luxSmutant demonstrated a complete loss of ability to colonize the intestinal tract. In the pregnant model, the mutant also failed to induce abortion, while the wild-type strain was highly abortifacient. Genetic complementation of theluxSgene fully restored the virulent phenotype in both models. Interestingly, when the organism was inoculated into guinea pigs by the intraperitoneal route, no difference in virulence (abortion induction) was observed between theluxSmutant and the wild-type strain, suggesting that the defect in virulence following oral inoculation is likely associated with a defect in colonization and/or translocation of the organism out of the intestine. These studies provide the first direct evidence that LuxS plays an important role in the virulence ofC. jejuniusing anin vivomodel of natural disease.


2021 ◽  
Vol 22 (11) ◽  
pp. 5711
Author(s):  
Julian Zacharjasz ◽  
Anna M. Mleczko ◽  
Paweł Bąkowski ◽  
Tomasz Piontek ◽  
Kamilla Bąkowska-Żywicka

Knee osteoarthritis (OA) is a degenerative knee joint disease that results from the breakdown of joint cartilage and underlying bone, affecting about 3.3% of the world's population. As OA is a multifactorial disease, the underlying pathological process is closely associated with genetic changes in articular cartilage and bone. Many studies have focused on the role of small noncoding RNAs in OA and identified numbers of microRNAs that play important roles in regulating bone and cartilage homeostasis. The connection between other types of small noncoding RNAs, especially tRNA-derived fragments and knee osteoarthritis is still elusive. The observation that there is limited information about small RNAs different than miRNAs in knee OA was very surprising to us, especially given the fact that tRNA fragments are known to participate in a plethora of human diseases and a portion of them are even more abundant than miRNAs. Inspired by these findings, in this review we have summarized the possible involvement of microRNAs and tRNA-derived fragments in the pathology of knee osteoarthritis.


Biology ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 486
Author(s):  
Sílvia C. Rodrigues ◽  
Renato M. S. Cardoso ◽  
Filipe V. Duarte

The most famous role of mitochondria is to generate ATP through oxidative phosphorylation, a metabolic pathway that involves a chain of four protein complexes (the electron transport chain, ETC) that generates a proton-motive force that in turn drives the ATP synthesis by the Complex V (ATP synthase). An impressive number of more than 1000 mitochondrial proteins have been discovered. Since mitochondrial proteins have a dual genetic origin, it is predicted that ~99% of these proteins are nuclear-encoded and are synthesized in the cytoplasmatic compartment, being further imported through mitochondrial membrane transporters. The lasting 1% of mitochondrial proteins are encoded by the mitochondrial genome and synthesized by the mitochondrial ribosome (mitoribosome). As a result, an appropriate regulation of mitochondrial protein synthesis is absolutely required to achieve and maintain normal mitochondrial function. Regarding miRNAs in mitochondria, it is well-recognized nowadays that several cellular mechanisms involving mitochondria are regulated by many genetic players that originate from either nuclear- or mitochondrial-encoded small noncoding RNAs (sncRNAs). Growing evidence collected from whole genome and transcriptome sequencing highlight the role of distinct members of this class, from short interfering RNAs (siRNAs) to miRNAs and long noncoding RNAs (lncRNAs). Some of the mechanisms that have been shown to be modulated are the expression of mitochondrial proteins itself, as well as the more complex coordination of mitochondrial structure and dynamics with its function. We devote particular attention to the role of mitochondrial miRNAs and to their role in the modulation of several molecular processes that could ultimately contribute to tissue regeneration accomplishment.


2017 ◽  
Vol 85 (6) ◽  
Author(s):  
Orhan Sahin ◽  
Samantha A. Terhorst ◽  
Eric R. Burrough ◽  
Zhangqi Shen ◽  
Zuowei Wu ◽  
...  

ABSTRACT Campylobacter jejuni is a zoonotic pathogen, and a hypervirulent clone, named clone SA, has recently emerged as the predominant cause of ovine abortion in the United States. To induce abortion, orally ingested Campylobacter must translocate across the intestinal epithelium, spread systemically in the circulation, and reach the fetoplacental tissue. Bacterial factors involved in these steps are not well understood. C. jejuni is known to produce capsular polysaccharide (CPS), but the specific role that CPS plays in systemic infection and particularly abortion in animals remains to be determined. In this study, we evaluated the role of CPS in bacteremia using a mouse model and in abortion using a pregnant guinea pig model following oral challenge. Compared with C. jejuni NCTC 11168 and 81-176, a clone SA isolate (IA3902) resulted in significantly higher bacterial counts and a significantly longer duration of bacteremia in mice. The loss of capsule production via gene-specific mutagenesis in IA3902 led to the complete abolishment of bacteremia in mice and abortion in pregnant guinea pigs, while complementation of capsule expression almost fully restored these phenotypes. The capsule mutant strain was also impaired for survival in guinea pig sera and sheep blood. Sequence-based analyses revealed that clone SA possesses a unique CPS locus with a mosaic structure, which has been stably maintained in all clone SA isolates derived from various hosts and times. These findings establish CPS as a key virulence factor for the induction of systemic infection and abortion in pregnant animals and provide a viable candidate for the development of vaccines against hypervirulent C. jejuni.


2011 ◽  
Vol 77 (20) ◽  
pp. 7227-7235 ◽  
Author(s):  
William W. Driscoll ◽  
John W. Pepper ◽  
Leland S. Pierson ◽  
Elizabeth A. Pierson

ABSTRACTBacteria rely on a range of extracellular metabolites to suppress competitors, gain access to resources, and exploit plant or animal hosts. The GacS/GacA two-component regulatory system positively controls the expression of many of these beneficial external products in pseudomonad bacteria. Natural populations often contain variants with defective Gac systems that do not produce most external products. These mutants benefit from a decreased metabolic load but do not appear to displace the wild type in nature. How could natural selection maintain the wild type in the presence of a mutant with enhanced growth? One hypothesis is that Gac mutants are “cheaters” that do not contribute to the public good, favored within groups but selected against between groups, as groups containing more mutants lose access to ecologically important external products. An alternative hypothesis is that Gac mutants have a mutualistic interaction with the wild type, so that each variant benefits by the presence of the other. In the biocontrol bacteriumPseudomonas chlororaphisstrain 30-84, Gac mutants do not produce phenazines, which suppress competitor growth and are critical for biofilm formation. Here, we test the predictions of these alternative hypotheses by quantifying interactions between the wild type and the phenazine- and biofilm-deficient Gac mutant within growing biofilms. We find evidence that the wild type and Gac mutants interact mutualistically in the biofilm context, whereas a phenazine-defective structural mutant does not. Our results suggest that the persistence of alternative Gac phenotypes may be due to the stabilizing role of local mutualistic interactions.


mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Adria Carbo ◽  
Danyvid Olivares-Villagómez ◽  
Raquel Hontecillas ◽  
Josep Bassaganya-Riera ◽  
Rupesh Chaturvedi ◽  
...  

ABSTRACTThe development of gastritis duringHelicobacter pyloriinfection is dependent on an activated adaptive immune response orchestrated by T helper (Th) cells. However, the relative contributions of the Th1 and Th17 subsets to gastritis and control of infection are still under investigation. To investigate the role of interleukin-21 (IL-21) in the gastric mucosa duringH. pyloriinfection, we combined mathematical modeling of CD4+T cell differentiation within vivomechanistic studies. We infected IL-21-deficient and wild-type mice withH. pyloristrain SS1 and assessed colonization, gastric inflammation, cellular infiltration, and cytokine profiles. ChronicallyH. pylori-infected IL-21-deficient mice had higherH. pyloricolonization, significantly less gastritis, and reduced expression of proinflammatory cytokines and chemokines compared to these parameters in infected wild-type littermates. Thesein vivodata were used to calibrate anH. pyloriinfection-dependent, CD4+T cell-specific computational model, which then described the mechanism by which IL-21 activates the production of interferon gamma (IFN-γ) and IL-17 during chronicH. pyloriinfection. The model predicted activated expression of T-bet and RORγt and the phosphorylation of STAT3 and STAT1 and suggested a potential role of IL-21 in the modulation of IL-10. Driven by our modeling-derived predictions, we found reduced levels of CD4+splenocyte-specifictbx21androrcexpression, reduced phosphorylation of STAT1 and STAT3, and an increase in CD4+T cell-specific IL-10 expression inH. pylori-infected IL-21-deficient mice. Our results indicate that IL-21 regulates Th1 and Th17 effector responses during chronicH. pyloriinfection in a STAT1- and STAT3-dependent manner, therefore playing a major role controllingH. pyloriinfection and gastritis.IMPORTANCEHelicobacter pyloriis the dominant member of the gastric microbiota in more than 50% of the world’s population.H. pyloricolonization has been implicated in gastritis and gastric cancer, as infection withH. pyloriis the single most common risk factor for gastric cancer. Current data suggest that, in addition to bacterial virulence factors, the magnitude and types of immune responses influence the outcome of colonization and chronic infection. This study uses a combined computational and experimental approach to investigate how IL-21, a proinflammatory T cell-derived cytokine, maintains the chronic proinflammatory T cell immune response driving chronic gastritis duringH. pyloriinfection. This research will also provide insight into a myriad of other infectious and immune disorders in which IL-21 is increasingly recognized to play a central role. The use of IL-21-related therapies may provide treatment options for individuals chronically colonized withH. pylorias an alternative to aggressive antibiotics.


Sign in / Sign up

Export Citation Format

Share Document