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At least 19 recordsLinked to original sources
PubMed1978

Determination of the rates of synthesis and degradation of adenosine 3',5'-cyclic monophosphate in Escherichia coli CRP- and CRP+ strains.

We have developed a method for estimating the rates of synthesis and degradation of adenosine 3',5'-cyclic monophosphate (cAMP) in Escherichia coli during balanced growth. Applying this method, we have found that an E. coli CRP- mutant 5333 (deficient for cAMP receptor protein) synthesizes cAMP about 25 times faster than does its CRP+ parent 1100. This accounts for the abnormally high intracellular and extracellular cAMP accumulation in 5333.

Cyclic AMP↗
PubMed2026

Actuation of CRP activating region 3 by acetylation modulates V. cholerae sugar utilization and virulence.

UNLABELLED: The cyclic AMP receptor protein or CRP is a global regulator of bacterial metabolism that activates transcription of genes required for utilization of alternative carbon sources in response to the second messenger cAMP, which is synthesized in the setting of glucose scarcity. CRP activates transcription through contact with RNA polymerase at three sites termed activating regions (ARs) 1-3. AR3 was previously reported to be functional only when CRP K52 was mutated to a neutral residue and to be essential for transcription only in the absence of AR1 and AR2. Multiple proteomic studies have reported acetylation of CRP K52. This post-translational modification is predicted to activate AR3. To probe the role of K52 acetylation (K52QAc) and AR3 at the genome level, we used ChIP-seq and RNA-seq analysis to compare WT CRP with a CRP K52Q mutant that mimics CRP K52Ac. We report that CRP K52Q binds to hundreds of new sites on the chromosome, resulting in increased abundance of known as well as previously unknown transcripts. These transcripts increase uptake and metabolism of dietary sugars such as maltose and galactose, repress acetate consumption, and augment virulence gene expression. We attribute the repression of acetate consumption to a novel small RNA, CrbZ, which is positively regulated by CRP K52Q in LB broth and by WT CRP specifically in minimal medium containing maltose. This study highlights the role of post-translational modifications in molding the CRP regulon to optimize pathogen metabolism and virulence gene expression in the human intestine in response to nutritional cues. SIGNIFICANCE STATEMENT: As a model in the field of bacterial transcription, the structure and function of the cAMP receptor protein (CRP), a global transcription regulator, has been exhaustively investigated. These studies have established three activating regions (ARs) where CRP contacts RNA polymerase, of which only two were thought to participate in transcription activation by native CRP. Here we provide evidence that post-translational acetylation of V. cholerae CRP lysine 52 actuates AR3, enabling occupancy of hundreds of novel CRP binding sites and the transcription of genes encoding novel small RNAs. These changes alter virulence gene expression, promote utilization of dietary carbon sources, and delay acetate uptake. We propose that acetylation of CRP K52 engages AR3, thus optimizing V. cholerae fitness in the human intestine.

Journal Article↗
PubMed1979

C-reactive protein (CRP) in early diagnosis of neonatal septicemia.

The usefulness of CRP in early detection of neonatal septicemia/meningitis and urinary tract infection was studied in a neonatal unit using a semiquantitative latex-agglutination as a rapid screening method, and electroimmuno assay as reference method for CRP determination. In 94% of non-infected infants CRP was less than or equal to 15 mg/l and 82% had CRP less than 10 mg/l up to 3 days of age. After 3 days of age 96% had CRP less than 10 mg/l. The initial CRP level was increased in 16 out of 18 patients (89%) with bacterial septicemia. Low CRP was seen in one patient with total agranulocytosis and septicemia from Streptococcus type B and in one patient with Staphylococcus albus sepsis. A rise in CRP was also seen in very pre-term infants with septicemia. Increased initial CRP was uncommon in neonatal urinary tract infection (2 of 9), but a rise was seen in 3 additional patients. A comparison between CRP, total neutrophil blood cell count and band neutrophil count as diagnostic parameters was in favour of CRP at this early stage of infection. CRP is of definite value as an aid in early diagnosis of neonatal septicemia and bacterial meningitis.

C-Reactive Protein↗
PubMed2025

GWAS of CRP response to statins further supports the role of APOE in statin response: A GIST consortium study.

Statins are first-line treatments in the primary and secondary prevention of cardiovascular disease. Clinical studies show statins act independently of lipid-lowering mechanisms to decrease C-reactive protein (CRP), an inflammation marker. We aim to elucidate genetic loci associated with CRP statin response. CRP statin response is the change in log-CRP between off-treatment and on-treatment measurements. Cohort-level Genome-Wide Association Studies (GWAS) of CRP response were performed using 1000 Genomes imputed data, testing &#x223c;10 million common genetic variants. GWAS meta-analysis combined results from seven cohorts and clinical trials totalling 14,070 statin-treated individuals of European ancestry within the GIST consortium. Secondary analyses included statin-by-placebo interaction analyses, and lookups in African ancestry cohorts. Our GWAS identified two genome-wide significant (P&#x202f;<&#x202f;5e-8) loci: APOE and HNF1A for CRP statin response corrected for baseline CRP. The missense lead variant rs429358 at APOE, contributing to the APOE-E4 haplotype, is a risk locus for dyslipidaemia, Alzheimer's and coronary artery disease (CAD). The HNF1A locus is associated with diabetes, cholesterol levels, and CAD. Both loci are also associated with baseline CRP levels, and neither locus achieved a significant (P&#x202f;<&#x202f;0.05) result from the statin v. placebo interaction meta-analysis using randomized clinical trial data. However, the interaction result (P-int=0.09) for APOE was suggestive and possibly underpowered. The APOE-E4 signal may therefore be associated with both CRP and LDL-cholesterol statin response. Combined with suggestions in the literature that APOE also leads to differential statin benefit in Alzheimer's, the APOE locus warrants further investigation for potential genetic effects on healthcare with statin treatment.

Humans↗
PubMed1979

[Enhanced UV sensitivity of Escherichia coli strain uvrA crp].

UV-sensitivity and UV-induced mutability to tryptophan independence has been studied in isogenic crp, cya, crp+, uvrA crp and uvrA crp+ strains of Escherichia coli. crp and cya strains are found to have the same UV-sensitivity as an isogenic wild type strain. UV-sensitivity of uvrA crp strain seems to be one-two orders increased as compared with the sensitivity exhibited by the uvrA - crp+ strain. The yield of UV-induced revertants is slightly higher in crp, cya and uvrA crp strains than in the wild type cells. The existence of cap-dependent inducible error-free repair pathway is supposed due to the data obtained.

DNA Repair↗
PubMed1977

Effects of C-reactive protein on platelet function. III. The role of cAMP, contractile elements, and prostaglandin metabolism in CRP-induced inhibition of platelet aggregation and secretion.

It was previously demonstrated that C-reactive protein (CRP) inhibits platelet aggregation and release reactions, activation of platelet factor 3, and platelet-dependent clot retraction. Multiple considerations including selective inhibition of secondary wave aggregation suggested that CRP exerted its inhibitory effects by interfering with the release of endogenous ADP. In the present investigation, CRP was found by direct assay to inhibit the release of endogenous ADP and/or serotonin concomitant with inhibition of platelet aggregation stimulated by ADP, epinephrine, thrombin, and AHGG. CRP did not induce an increase in the basal level of platelet cAMP, suggesting independence of a direct effect upon this mediator system. Furthermore, CRP did not inhibit the aggregation and secretion induced by the antibiotic ionophore A23187, suggesting the absence of a direct effect upon the activation of platelet contractile elements. By contrast, CRP did inhibit both thrombin-induced release of malondialdehyde, a prostaglandin endoperoxide nonprostanoate endproduct, and platelet aggregation induced by the prostaglandin endoperoxide precursor arachidonic acid. These data, therefore, raise the possibility that CRP inhibits platelet reactivities by interfering with an aspect of porstaglandin metabolism, and that this occurs subsequent to the hydrolytic accumulation of arachidonic acid and prior to the movement of calcium from the platelet dense tubules. These studies support the concept that CRP serves to modulate platelet reactivities during acute inflammatory reactions.

Adenosine Diphosphate↗
PubMed1976

Multiple regulation of nucleoside catabolizing enzymes in Escherichia coli: effects of 3:5' cyclic AMP and CRP protein.

The regulation of the synthesis of nucleoside metabolizing enzymes has been studied in cya and crp mutant strains of Escherichia coli. The synthesis of the cyt-enzymes, cytidine deaminase and uridine phosphorylase regulated by the cytR gene product, is activated by the cAMP-CRP complex. On the other hand the synthesis of the deoenzymes: deoxyriboaldolase, thymidine phosphorylase, phosphodeoxyribomutase and purine nucleoside phosphorylase, appears to be increased if an active cAMP-CRP complex cannot be formed. It also seems that nucleosides serve as poor carbon sources for cya and crp mutants; this could not solely be explained by low levels of nucleoside metabolizing enzymes nor by a deficiency in nucleoside uptake. Addition of casamino acids stimulated the growth of cya and crp mutants, with nucleosides as carbon sources. When grown on glucose and casamino acids growth could be stimulated by adenine and hypoxanthine nucleosides; these results suggest an impaired nitrogen metabolism in cya and crp mutants.

Conjugation, Genetic↗
PubMed1979

Non-specific interactions of CRP from E. coli with native and denatured DNAs: control of binding by cAMP and cGMP and by cation concentration.

The cyclic adenosine 3',5'-monophosphate receptor protein of Escherichia coli (CRP) binds cooperatively to single- and double-stranded DNA. Binding data could be fitted to the model of McGhee and von Hippel (1) and show that neither strandedness of DNA, nor the effectors cAMP and cGMP or the ionic strength (KCl) do change appreciably the cooperativity parameter omega (omega approximately or equal to 100), and site size of DNA. Instead, distinctly different slopes were observed for the linear decrease of log K omega (a measure of the overall affinity) as a function of log (K+). From these double-log plots (2), the number of cations released and the non-electrostatic contributions to the binding free energy could be determined. Binding of CRP to single-stranded DNA is slightly favored under physiological ionic conditions (0.15-0.20 M), but such a preferential binding is almost abolished in the presence of cAMP which increases the strength of the interaction of the protein with both forms of DNA. CGMP does not change the binding properties and interactions of CRP with DNA. These observations do not support the proposal that the cAMP-CRP complex could stimulate transcription via some "melting" property unless its interactions be dramatically changed when it binds specifically to promoter DNA.

Bacteriophage lambda↗
PubMed1975

Deletion of the Escherichia coli crp gene.

Spontaneous crp mutants Escherichia coli were selected from a strain that does not require 3',5'-cyclic adenosine monophosphate for CAP activity. Several deletions of the crp gene were characterized. The crp gene was not essential for growth of E. coli. crp mutations reduced the donor ability of Hfr strains.

Adenylyl Cyclases↗
PubMed1976

Effects of crp mutations on adenosine 3',5'-monophosphate metabolism in Salmonella typhimurium.

Wild-type Salmonella typhimurium could not grow with exogenous cyclic adenosine 3',5'-monophosphate (AMP) as the sole source of phosphate, but mutants capable of cyclic AMP utilization could be isolated provided the parental strain contained a functional cyclic AMP phosphodiesterase.All cyclic AMP-utilizing mutants had the growth and fermentation properties of cyclic AMP receptor protein (crp) mutants, and some lacked cyclic AMP binding activity in vitro. The genetic defect in each such mutant was due to a single point mutation, which was co-transducible with cysG. crp mutants isolated by alternative procedures also exhibited the capacity to utilize cyclic AMP. crp mutants synthesized cyclic AMP at increased rates and contained enhanced cellular cyclic AMP levels relative to the parental strains, regardless of whether or not cyclic AMP phosphodiesterase was active. Moreover, adenylate cyclase activity in vivo was less sensitive to regulation by glucose, possibly because the enzyme II complexes of the phosphotransferase system, responsible for glucose transport and phosphorylation, could not be induced to maximal levels. This possibility was strengthened by the observation that enzyme II activity (measured both in vitro by sugar phosphorylation and in vivo by sugar transport and chemotaxis) was inducible in the parental strain but not in crp mutants. The results suggest that the cyclic AMP receptor protein regulates cyclic AMP metabolism as well as catabolic enzyme synthesis.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2026

Associations between CRP-related DNA methylation, stress exposure, and depression severity in a longitudinal clinical cohort.

BACKGROUND: Environmental adversity is linked to major depressive disorder (MDD), potentially via sustained low-grade inflammation. However, serum markers such as C-reactive protein (CRP) are transient and sensitive to acute states. In contrast, epigenetic signatures of inflammation may provide a more stable trace of how stress becomes biologically embedded and contributes to depression risk over time. METHODS: In a subsample of the Marburg-M&#xfc;nster Affective Disorders Cohort Study (MACS; N&#xa0;=&#xa0;579; 320 healthy controls, 259 with MDD), we examined whether early life adversity (ELA; CTQ) and recent life stress (RLS; LEQ) are associated with CRP-related DNA methylation (CRPm) at baseline. We further tested whether CRPm predicts depressive symptom severity (HAMD) at baseline and at two-year follow-up (n&#xa0;=&#xa0;407). DNA was extracted from whole blood, and CRPm scores were computed using publicly available genome-wide summary statistics. RESULTS: CRPm explained 21.3% of the variance in serum high-sensitivity CRP (hsCRP). Higher CRPm was significantly associated with both ELA (b&#xa0;=&#xa0;0.01, SE&#xa0;=&#xa0;0.003, p&#xa0;=&#xa0;0.017) and RLS (b&#xa0;=&#xa0;0.01, SE&#xa0;=&#xa0;0.004, p&#xa0;=&#xa0;0.032), after adjusting for age and sex. CRPm also predicted depressive symptom severity at baseline (b&#xa0;=&#xa0;0.68, SE&#xa0;=&#xa0;0.27, p&#xa0;=&#xa0;0.013) and at follow-up (b&#xa0;=&#xa0;0.79, SE&#xa0;=&#xa0;0.25, p&#xa0;=&#xa0;0.002). These associations remained after controlling for white blood cell-type composition but were attenuated after adjusting for BMI and smoking. In contrast, hsCRP was not associated with adversity or depressive symptoms. CONCLUSION: Our study indicates that a methylation-based index of chronic inflammation is associated with stress exposure and depressive symptoms over time, in contrast to fluctuating serum hsCRP. The findings are more consistent with an indirect pathway in which environmental adversity is linked to inflammatory biology via stress-related health behaviors, rather than with a model of direct biological embedding.

Humans↗
PubMed1978

Transport of antibiotics and metabolite analogs by systems under cyclic AMP control: positive selection of Salmonella typhimurium cya and crp mutants.

Mutants in the cyclic AMP (cAMP) control system in Salmonella typhimurium (cya = adenyl cyclase, crp = cAMP receptor protein) were partially resistant to growth inhibition by 22 antibiotics (including fosfomycin, nalidixic acid, and streptomycin) and 29 inhibitory analogs of normal bacterial fuel/carbon sources. This resistance was used as the basis for an efficient positive selection of cya and crp mutants. We propose that these antibiotics and analogs enter the bacteria through transport systems normally used for transporting fuel/carbon sources and that this is accomplished because of a structural similarity between the antibiotic and the natural substrate of the particular transport system involved. We propose that these transport systems are all under positive control by cAMP and that cAMP acts as a signal molecule (alarmone) for fuel/carbon deprivation. Evidence is provided for a hierarchy within operons controlled by cAMP. The methodology is shown to be useful for analyzing both antibiotic transport systems and the cAMP super-control system.

Amino Acids↗
PubMed1979

[Cooperative non-specific binding of the cyclic adenosine 3'--5'-monophosphate receptor protein (CRP) from Escherichia coli to double-stranded thymus and lambda pgal DNA].

Either free or combined with cAMP, CRP binds cooperatively to double-stranded thymus and lambda pgal DNA. The affinity of CRP for both DNAs in these non-specific interactions is increased by cAMP without noticeable change in the degree of cooperativity. Values of the intrinsic association constant, cooperativity parameter, and site size of DNA were determined from ultracentrifugal investigations under near-physiological ionic conditions.

Animals↗
PubMed1977

[The protecting action of a combination of vasoactivating substances (CRP) on disturbances of the cerebral blood flow and metabolism and the cortical electrical activity (author's transl)].

The effect of anoxia and direct cortical stimulation was investigated in control, hypotensive and post reinfusional periods, before and after treatment with a combination of coumarin/rutin sulphate sodium salts/proxyphylline (CRP, Theokal). Theokal lowered the mean arterial pressure and a slight NADH oxidation appeared. Blood flow did not change after Theokal in spite of the 30 mm Hg blood pressure drop. This suggests an improved oxygen supply to the cortical cells. The increase in anoxic NADH reaction and the faster reoxidation kinetics of NADH following anoxia provided further evidence for the beneficial effect of Theokal on brain circulation and metabolism. It is to be emphasized that the described action of the drug can be observed only in hemorrhagic shock but not in normal animals.

Animals↗
PubMed2026

Effect of Semaglutide on the Inflammatory Biomarker High-Sensitivity CRP in Patients With Established Cardiovascular Disease and Overweight or Obesity in SELECT: A Prespecified Secondary Analysis.

BACKGROUND: In SELECT (Semaglutide Effects on Heart Disease and Stroke in Patients With Overweight or Obesity), among 17&#x2009;604 patients with known atherosclerotic cardiovascular disease and overweight or obesity, but not diabetes, randomization to the glucagon-like peptide-1 receptor agonist semaglutide significantly reduced the primary outcome of major adverse cardiovascular events (MACE; cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke) compared with placebo (mean follow-up, 39.8 months). Inflammation, as indicated by plasma hsCRP (high-sensitivity C-reactive protein) level, is implicated as a biomarker predicting cardiovascular risk in obesity and atherosclerotic cardiovascular disease. SELECT provides a unique opportunity to study the relationship among hsCRP, obesity, weight loss, and MACE outcomes in semaglutide versus placebo groups. METHODS: In this prespecified SELECT substudy, we evaluated whether baseline hsCRP levels predicted MACE risk and examined the relationships between changes in hsCRP levels and time to first MACE, baseline body weight, weight loss, and other clinical measures among treatment groups over time (104, 208 weeks) using multiple approaches, including Cox modeling. RESULTS: Baseline hsCRP level, which was similar in the semaglutide (geometric mean 1.96 mg/L) and placebo (geometric mean 1.91 mg/L) groups, was prognostic of future MACE. The risk of MACE increased across baseline hsCRP level <2, 2-<10, and &#x2265;10 mg/L subgroups, including significant associations with cardiovascular and all-cause death. Semaglutide reduced hsCRP levels (-37.8% [104 weeks]) and risk of MACE across all hsCRP subgroups. Greater reductions in ratio-to-baseline hsCRP with semaglutide were associated with greater weight loss, but preceded major weight loss, evident by 4 and 8 weeks, and occurred among those without weight loss. Semaglutide-associated changes in hsCRP were independent of low-density lipoprotein cholesterol levels, statin use, and atherosclerotic cardiovascular disease entry criteria. hsCRP reductions were found to be prognostic of decreased risk of MACE. Modeling suggests decreased inflammation as contributing in part to the benefits seen with semaglutide in SELECT. CONCLUSIONS: In SELECT, hsCRP data at baseline and in response to treatment with semaglutide support inflammation as a potential prognostic factor associated with cardiovascular risk in these generally well-treated patients with atherosclerotic cardiovascular disease and overweight or obesity but not diabetes. These findings suggest that the MACE reduction observed with semaglutide versus placebo in SELECT may have partially involved a decrease in inflammation. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03574597.

Humans↗