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PLoS Biology May 2024The peptidoglycan (PG) layer is a critical component of the bacterial cell wall and serves as an important target for antibiotics in both gram-negative and gram-positive...
The peptidoglycan (PG) layer is a critical component of the bacterial cell wall and serves as an important target for antibiotics in both gram-negative and gram-positive bacteria. The hydrolysis of septal PG (sPG) is a crucial step of bacterial cell division, facilitated by FtsEX through an amidase activation system. In this study, we present the cryo-EM structures of Escherichia coli FtsEX and FtsEX-EnvC in the ATP-bound state at resolutions of 3.05 Å and 3.11 Å, respectively. Our PG degradation assays in E. coli reveal that the ATP-bound conformation of FtsEX activates sPG hydrolysis of EnvC-AmiB, whereas EnvC-AmiB alone exhibits autoinhibition. Structural analyses indicate that ATP binding induces conformational changes in FtsEX-EnvC, leading to significant differences from the apo state. Furthermore, PG degradation assays of AmiB mutants confirm that the regulation of AmiB by FtsEX-EnvC is achieved through the interaction between EnvC-AmiB. These findings not only provide structural insight into the mechanism of sPG hydrolysis and bacterial cell division, but also have implications for the development of novel therapeutics targeting drug-resistant bacteria.
Topics: Peptidoglycan; Cell Division; Hydrolysis; Escherichia coli Proteins; Escherichia coli; Adenosine Triphosphate; Cryoelectron Microscopy; Cell Wall; Protein Conformation; Models, Molecular; N-Acetylmuramoyl-L-alanine Amidase; Bacterial Outer Membrane Proteins; ATP-Binding Cassette Transporters; Cystic Fibrosis Transmembrane Conductance Regulator; Lipoproteins; Cell Cycle Proteins
PubMed: 38814940
DOI: 10.1371/journal.pbio.3002628 -
Frontiers in Bioscience (Landmark... May 2024Changes in myocardial mitochondrial morphology and function in premature ventricular contractions (PVCs)-induced cardiomyopathy (PVCCM) remain poorly studied. Here, we...
AIMS
Changes in myocardial mitochondrial morphology and function in premature ventricular contractions (PVCs)-induced cardiomyopathy (PVCCM) remain poorly studied. Here, we investigated the effects of PVCs with different coupling intervals (CIs) on myocardial mitochondrial remodelling in a canine model of PVCCM.
METHODS AND RESULTS
Twenty-one beagles underwent pacemaker implantation and were randomised into the sham (n = 7), short-coupled PVCs (SCP, n = 7), and long-coupled PVCs (LCP, n = 7) groups. Right ventricular (RV) apical bigeminy was produced for 12-week to induce PVCCM in the SCP (CI, 250 ms) and LCP (CI, 350 ms) groups. Echocardiography was performed at baseline and biweekly thereafter to evaluate cardiac function. Masson's trichrome staining measured ventricular interstitial fibrosis. The ultrastructural morphology of the myocardial mitochondria was analysed using transmission electron microscopy. Mitochondrial Ca2+ concentration, reactive oxygen species (ROS) levels, adenosine triphosphate (ATP) content, membrane potential, and electron transport chain (ETC) complex activity were measured to assess myocardial mitochondrial function. Twelve-week-PVCs led to left ventricular (LV) enlargement with systolic dysfunction, disrupted mitochondrial morphology, increased mitochondrial Ca2+ concentration and ROS levels, decreased mitochondrial ATP content and membrane potential, and impaired ETC complex activity in both the SCP and LCP groups (all < 0.01 the sham group). Ventricular fibrosis was observed only in canines with LCP. Worse cardiac function and more pronounced abnormalities in mitochondrial morphology and function were observed in the LCP group than to the SCP group (all < 0.05).
CONCLUSION
We demonstrated myocardial mitochondrial abnormalities in dogs with PVCCM, characterised by abnormal mitochondrial morphology, mitochondrial Ca2+ overload, oxidative stress, and impaired mitochondrial energy metabolism. Compared to SCP, long-term LCP exposure resulted in more severe mitochondrial remodelling and cardiac dysfunction in dogs.
Topics: Animals; Dogs; Mitochondria, Heart; Cardiomyopathies; Disease Models, Animal; Ventricular Premature Complexes; Reactive Oxygen Species; Calcium; Male; Adenosine Triphosphate; Membrane Potential, Mitochondrial; Echocardiography
PubMed: 38812311
DOI: 10.31083/j.fbl2905200 -
Communications Biology May 2024Propionic acidemia (PA), resulting from Pcca or Pccb gene mutations, impairs propionyl-CoA metabolism and induces metabolic alterations. While speculation exists that...
Propionic acidemia (PA), resulting from Pcca or Pccb gene mutations, impairs propionyl-CoA metabolism and induces metabolic alterations. While speculation exists that fasting might exacerbate metabolic crises in PA patients by accelerating the breakdown of odd-chain fatty acids and amino acids into propionyl-CoA, direct evidence is lacking. Our investigation into the metabolic effects of fasting in Pcca(A138T) mice, a PA model, reveals surprising outcomes. Propionylcarnitine, a PA biomarker, decreases during fasting, along with the C3/C2 (propionylcarnitine/acetylcarnitine) ratio, ammonia, and methylcitrate. Although moderate amino acid catabolism to propionyl-CoA occurs with a 23-h fasting, a significant reduction in microbiome-produced propionate and increased fatty acid oxidation mitigate metabolic alterations by decreasing propionyl-CoA synthesis and enhancing acetyl-CoA synthesis. Fasting-induced gluconeogenesis further facilitates propionyl-CoA catabolism without changing propionyl-CoA carboxylase activity. These findings suggest that fasting may alleviate metabolic alterations in Pcca(A138T) mice, prompting the need for clinical evaluation of its potential impact on PA patients.
Topics: Animals; Mice; Fasting; Methylmalonyl-CoA Decarboxylase; Mutation; Propionic Acidemia; Male; Mice, Knockout; Disease Models, Animal; Mice, Inbred C57BL; Acyl Coenzyme A
PubMed: 38811689
DOI: 10.1038/s42003-024-06362-8 -
Scientific Reports May 2024Age-related decline in mobility and cognition are associated with cellular senescence and NAD + depletion in dogs and people. A combination of a novel...
Age-related decline in mobility and cognition are associated with cellular senescence and NAD + depletion in dogs and people. A combination of a novel NAD + precursor and senolytic, LY-D6/2, was examined in this randomized controlled trial. Seventy dogs with mild to moderate cognitive impairment were enrolled and allocated into placebo, low or full dose groups. Primary outcomes were change in cognitive impairment measured with the owner-reported Canine Cognitive Dysfunction Rating (CCDR) scale and change in activity measured with physical activity monitors. Fifty-nine dogs completed evaluations at the 3-month primary endpoint, and 51 reached the 6-month secondary endpoint. There was a significant difference in CCDR score across treatment groups from baseline to the primary endpoint (p = 0.02) with the largest decrease in the full dose group. No difference was detected between groups using in house cognitive testing. There were no significant differences between groups in changes in measured activity. The proportion of dogs that improved in frailty and owner-reported activity levels and happiness was higher in the full dose group than other groups, however this difference was not significant. Adverse events occurred equally across groups. All groups showed improvement in cognition, frailty, and activity suggesting placebo effect and benefits of trial participation. We conclude that LY-D6/2 improves owner-assessed cognitive function over a 3-month period and may have broader, but more subtle effects on frailty, activity and happiness as reported by owners.
Topics: Animals; Dogs; Male; Cognition; Female; Cognitive Dysfunction; NAD; Dog Diseases; Humans
PubMed: 38811634
DOI: 10.1038/s41598-024-63031-w -
Science Advances May 2024Cell motility universally relies on spatial regulation of focal adhesion complexes (FAs) connecting the substrate to cellular motors. In bacterial FAs, the Adventurous...
Cell motility universally relies on spatial regulation of focal adhesion complexes (FAs) connecting the substrate to cellular motors. In bacterial FAs, the Adventurous gliding motility machinery (Agl-Glt) assembles at the leading cell pole following a Mutual gliding-motility protein (MglA)-guanosine 5'-triphosphate (GTP) gradient along the cell axis. Here, we show that GltJ, a machinery membrane protein, contains cytosolic motifs binding MglA-GTP and AglZ and recruiting the MreB cytoskeleton to initiate movement toward the lagging cell pole. In addition, MglA-GTP binding triggers a conformational shift in an adjacent GltJ zinc-finger domain, facilitating MglB recruitment near the lagging pole. This prompts GTP hydrolysis by MglA, leading to complex disassembly. The GltJ switch thus serves as a sensor for the MglA-GTP gradient, controlling FA activity spatially.
Topics: Focal Adhesions; Bacterial Proteins; Guanosine Triphosphate; Protein Binding
PubMed: 38809974
DOI: 10.1126/sciadv.adn2789 -
Indian Journal of Pharmacology Mar 2024Sildenafil, a common over-the-counter pill often self-administered at high doses for erectile dysfunction, has been reported to rarely cause prothrombotic events and...
Off-target effect of high-dose sildenafil on adenosine 5'- diphosphate and collagen-induced platelet activation through mitogen-activated protein kinase pathway in treated BALB/C mice and in vitro experiments: A preliminary study.
Sildenafil, a common over-the-counter pill often self-administered at high doses for erectile dysfunction, has been reported to rarely cause prothrombotic events and sudden cardiac death in a few case reports. Therefore, we investigated the in vitro and in vivo effect of sildenafil treatment and dosage on platelet activation and mitogen-activated protein kinase (MAPK) phosphorylation. BALB/C mice were segregated into four groups, each having four mice each (control, low [3.25 mg/kg], medium [6.5 mg/kg], and high [13 mg/kg] sildenafil), and after the treatment, blood was drawn from each mouse and washed platelets prepared. Washed platelets were incubated with CD41 PE-Cy7 and Phospho-p38 MAPK PE antibodies and analyzed using a flow cytometer for platelet activation and adenosine 5'- diphosphate (ADP)/collagen-induced MAPK phosphorylation. Washed platelets obtained from the venous blood of 18 human volunteers, were incubated with PAC-1 FITC and Phospho-p38 MAPK PE antibodies, and platelet activation (ADP and collagen), followed by flow cytometry analysis. There was a significant increase in both platelet activation as well as MAPK phosphorylation in the presence of collagen in the high-dose (13 mg/kg) sildenafil group (P = 0.000774). Further, increased platelet activation was observed in samples that were treated with high-dose sildenafil as compared to the untreated samples (P < 0.00001). These studies show the risk of prothrombotic episodes in patients on high-dose sildenafil (100 mg), in those with even mild endothelial dysfunction due to ADP, and collagen-induced platelet activation through MAPK phosphorylation, which was not seen in the low-and intermediate-dose cohorts.
Topics: Animals; Sildenafil Citrate; Platelet Activation; Mice, Inbred BALB C; Male; Humans; Collagen; Mice; Adenosine Diphosphate; Blood Platelets; Phosphorylation; Mitogen-Activated Protein Kinases; MAP Kinase Signaling System; Phosphodiesterase 5 Inhibitors; Dose-Response Relationship, Drug; Adult
PubMed: 38808925
DOI: 10.4103/ijp.ijp_312_23 -
Journal of Nanobiotechnology May 2024Ulcerative colitis (UC) is one chronic and relapsing inflammatory bowel disease. Macrophage has been reputed as one trigger for UC. Recently, phosphodiesterase 4 (PDE4)...
BACKGROUND
Ulcerative colitis (UC) is one chronic and relapsing inflammatory bowel disease. Macrophage has been reputed as one trigger for UC. Recently, phosphodiesterase 4 (PDE4) inhibitors, for instance roflumilast, have been regarded as one latent approach to modulating macrophage in UC treatment. Roflumilast can decelerate cyclic adenosine monophosphate (cAMP) degradation, which impedes TNF-α synthesis in macrophage. However, roflumilast is devoid of macrophage-target and consequently causes some unavoidable adverse reactions, which restrict the utilization in UC.
RESULTS
Membrane vesicles (MVs) from probiotic Escherichia coli Nissle 1917 (EcN 1917) served as a drug delivery platform for targeting macrophage. As model drugs, roflumilast and MnO were encapsulated in MVs (Rof&MnO@MVs). Roflumilast inhibited cAMP degradation via PDE4 deactivation and MnO boosted cAMP generation by activating adenylate cyclase (AC). Compared with roflumilast, co-delivery of roflumilast and MnO apparently produced more cAMP and less TNF-α in macrophage. Besides, Rof&MnO@MVs could ameliorate colitis in mouse model and regulate gut microbe such as mitigating pathogenic Escherichia-Shigella and elevating probiotic Akkermansia.
CONCLUSIONS
A probiotic-based nanoparticle was prepared for precise codelivery of roflumilast and MnO into macrophage. This biomimetic nanoparticle could synergistically modulate cAMP in macrophage and ameliorate experimental colitis.
Topics: Animals; Aminopyridines; Mice; Cyclic AMP; Probiotics; Cyclopropanes; Manganese Compounds; Benzamides; Oxides; Macrophages; Phosphodiesterase 4 Inhibitors; Colitis; RAW 264.7 Cells; Escherichia coli; Tumor Necrosis Factor-alpha; Mice, Inbred C57BL; Male; Disease Models, Animal
PubMed: 38807127
DOI: 10.1186/s12951-024-02558-6 -
Cellular and Molecular Life Sciences :... May 2024Aspergillus ochraceus is the traditional ochratoxin A (OTA)-producing fungus with density-dependent behaviors, which is known as quorum sensing (QS) that is mediated by...
Aspergillus ochraceus is the traditional ochratoxin A (OTA)-producing fungus with density-dependent behaviors, which is known as quorum sensing (QS) that is mediated by signaling molecules. Individual cells trend to adapt environmental changes in a "whole" flora through communications, allowing fungus to occupy an important ecological niche. Signals perception, transmission, and feedback are all rely on a signal network that constituted by membrane receptors and intracellular effectors. However, the interference of density information in signal transduction, which regulates most life activities of Aspergillus, have yet to be elucidated. Here we show that the G protein-coupled receptor (GPCR) to cAMP pathway is responsible for transmitting density information, and regulates the key point in life cycle of A. ochraceus. Firstly, the quorum sensing phenomenon of A. ochraceus is confirmed, and identified the density threshold is 10 spores/mL, which represents the low density that produces the most OTA in a series quorum density. Moreover, the GprC that classified as sugar sensor, and intracellular adenylate cyclase (AcyA)-cAMP-PKA pathway that in response to ligands glucose and HODEs are verified. Furthermore, GprC and AcyA regulate the primary metabolism as well as secondary metabolism, and further affects the growth of A. ochraceus during the entire life cycle. These studies highlight a crucial G protein signaling pathway for cell communication that is mediated by carbohydrate and oxylipins, and clarified a comprehensive effect of fungal development, which include the direct gene regulation and indirect substrate or energy supply. Our work revealed more signal molecules that mediated density information and connected effects on important adaptive behaviors of Aspergillus ochraceus, hoping to achieve comprehensive prevention and control of mycotoxin pollution from interrupting cell communication.
Topics: Quorum Sensing; Aspergillus ochraceus; Signal Transduction; Glucose; Cyclic AMP; Adenylyl Cyclases; Receptors, G-Protein-Coupled; Fungal Proteins; Ochratoxins
PubMed: 38806811
DOI: 10.1007/s00018-024-05160-z -
Acta Biochimica Et Biophysica Sinica May 2024Epigenetic modifications play an important role in cellular senescence, and enhancer of zeste homolog 2 (EZH2) is a key methyltransferase involved in epigenetic...
Epigenetic modifications play an important role in cellular senescence, and enhancer of zeste homolog 2 (EZH2) is a key methyltransferase involved in epigenetic remodeling in multiple myeloma (MM) cells. We have previously demonstrated that GSK126, a specific EZH2 inhibitor, exhibits anti-MM therapeutic efficacy and safety and ; however, its specific mechanism remains unclear. This study shows that GSK126 induces cellular senescence in MM, which is characterized by the accumulation of senescence-associated heterochromatin foci (SAHF) and p21, and increased senescence-associated β galactosidase activity. Furthermore, EZH2 is inhibited in ribonucleotide reductase regulatory subunit M2 (RRM2) overexpression OCI-MY5 and RPMI-8226 cells. RRM2 overexpression inhibits the methyltransferase function of EZH2 and promotes its degradation through the ubiquitin-proteasome pathway, thereby inducing cellular senescence. In this senescence model, Lamin B1, a key component of the nuclear envelope and a marker of senescence, does not decrease but instead undergoes aberrant accumulation. Meanwhile, phosphorylation of extracellular signal-regulated protein kinase (ERK1/2) is significantly increased. The inhibition of ERK1/2 phosphorylation in turn partially restores Lamin B1 level and alleviates senescence. These findings suggest that EZH2 inhibition increases Lamin B1 level and induces senescence by promoting ERK1/2 phosphorylation. These data indicate that EZH2 plays an important role in MM cellular senescence and provide insights into the relationships among Lamin B1, p-ERK1/2, and cellular senescence.
PubMed: 38804044
DOI: 10.3724/abbs.2024077 -
Infectious Diseases of Poverty May 2024Migrants, mainly undocumented and low-income refugees, are at high risk of hepatitis C virus (HCV) infection, but are a difficult-to-reach and to-treat population. The...
BACKGROUND
Migrants, mainly undocumented and low-income refugees, are at high risk of hepatitis C virus (HCV) infection, but are a difficult-to-reach and to-treat population. The aim of the study was to evaluate the effectiveness of a test and treat model with direct-acting antiviral for HCV infection in these migrants coming from low-income and living in southern Italy.
METHODS
A prospective, multicenter, collaborative study based on a four-phase-program (educational counseling, screening, linkage-to-care and treatment) was designed in southern Italy; the study started in June 2018, was stopped in February 2020 because of the outbreak of SARS-CoV2 infection in Italy and was resumed in February 2021 until November 2021. After educational counseling on infectious diseases that are transmitted through blood or sexually pseudonymized HCV screening was offered to all undocumented migrants and low-income refugees observed at one of the 1st level clinical centers. The HCV-RNA-positive subjects were referred to one of the 3rd level units of Infectious Diseases (ID) and treated with a 12-week course of sofosbuvir-velpatasvir and observed for 12 weeks after the end of direct antiviral agents (DAA) treatment.
STATISTICAL ANALYSIS
For the descriptive analysis, the categorical variables were reported as absolute numbers and relative frequencies. Continuous variables were summarized as mean and standard deviation (SD) if normally distributed, or as a median and interquartile range (IQR) if not normally distributed. We used Pearson chi-square or Fisher's exact test for categorical variables and Student's t test or Mann-Whitney test for continuous variables. A P value < 0.05 was considered to be statistically significant. Analyses were performed with SPSS 21.0.
RESULTS
Of the 3501migrants observed in the study period, 3417 (97.6%) agreed to be screened; 185 (4.7%) were anti-HCV-positive and, of these, 53 (28.6%) were HCV-RNA-positive. Of these 53 subjects, 48 (90.5%) were referred to an ID unit and started DAA treatment. The HCV-RNA-positive-subjects were older [median 36 years (IQR: 32-21) vs 27.19 (IQR: 30.5-19.25); P = 0.001], and less frequently males [35 (66.03 %) vs 119 (90.1%), P < 0 .0001] than seronegative participants. They more frequently came from Eastern Europe (70.8%) stayed longer in Italy [months of stay in Italy, mean ± SD: 51.02 ± 52.84 vs 25.7 ± 42.65, P = 0.001], and had more years of schooling [years of schooling, mean ± SD: 9.61±2.81 vs 7.10 ± 4, P = 0.0001]. HCV-RNA-positive-subjects less frequently reported piercing, tattoos and tribal scars as risk factors (23.6%). Of these 48 HCV RNA positive subjects who started DAA, 47 (97.9%) showed a sustained virological response and one dropped-out in follow-up after DAA treatment. No subject had any adverse event.
CONCLUSIONS
This model of HCV screening and linkage to care seems effective to eliminate HCV infectionin a difficult-to-reach and to-treat population, such as undocumented migrants and low-income refugees. The participation of cultural mediators in the study made possible a better interaction between migrants and physicians, as is evident from the large number of subjects enrolled. Eliminating HCV among migrants will have a long-term positive impact from a public health and healthcare perspective by reducing the number of individuals who potentially develop HCV-related complications such as liver cirrhosis and hepatocellular carcinoma and reducing the circulation of HCV in the regions that host them which often, as in the case of Italy, are low endemic for HCV infection.
Topics: Humans; Italy; Antiviral Agents; Prospective Studies; Male; Female; Adult; Middle Aged; Hepatitis C; Transients and Migrants; Hepacivirus; Sofosbuvir; Young Adult; Mass Screening; Refugees; Poverty
PubMed: 38802954
DOI: 10.1186/s40249-024-01200-9