Non-pathogenic microbiota accelerate age-related CpG Island methylation in colonic mucosa

DNA methylation is an epigenetic process altered in cancer and ageing. Age-related methylation drift can be used to estimate lifespan and can be influenced by extrinsic factors such as diet. Here, we report that non-pathogenic microbiota accelerate age-related methylation drift in the colon when compared with germ-free mice. DNA methylation analyses showed that microbiota and IL10KO were associated with changes in 5% and 4.1% of CpG sites, while mice with both factors had 18% alterations. Microbiota, IL10KO, and their combination altered 0.4%, 0.4%, and 4% of CpG island methylation, respectively. These are comparable to what is seen in colon cancer. Ageing changes were accelerated in the IL10KO mice with microbiota, and the affected genes were more likely to be altered in colon cancer. Thus, the microbiota affect DNA methylation of the colon in patterns reminiscent of what is observed in ageing and colorectal cancer.

DNA methylation entropy as a measure of stem cell replication and aging

BACKGROUND

Epigenetic marks are encoded by DNA methylation and accumulate errors as organisms age. This drift correlates with lifespan, but the biology of how this occurs is still unexplained. We analyze DNA methylation with age in mouse intestinal stem cells and compare them to nonstem cells.

RESULTS

Age-related changes in DNA methylation are identical in stem and nonstem cells, affect most prominently CpG islands and correlate weakly with gene expression. Age-related DNA methylation entropy, measured by the Jensen-Shannon Distribution, affects up to 25% of the detectable CpG sites and is a better measure of aging than individual CpG methylation. We analyze this entropy as a function of age in seven other tissues (heart, kidney, skeletal muscle, lung, liver, spleen, and blood) and it correlates strikingly with tissue-specific stem cell division rates. Thus, DNA methylation drift and increased entropy with age are primarily caused by and are sensors for, stem cell replication in adult tissues.

CONCLUSIONS

These data have implications for the mechanisms of tissue-specific functional declines with aging and for the development of DNA-methylation-based biological clocks.

Bioconvective Peristaltic Transport of a Nano Eyring-Powell Fluid in a Vertical Asymmetric Channel with Gyrotactic Microorganism

Peristaltic nanofluid’s flow due to the enhanced thermal performances of nanoparticles and their importance in many sectors play a vital role in medicine, cosmetics, manufacturing, and engineering processes. In this regard, the current theoretical work examines the swimming behavior of migratory gyrotactic microorganisms in a non- Newtonian blood-based nanofluid that is subjected to a magnetic field. The addition of motile microorganisms improves heat and mass transmission by stabilizing the nanoparticle suspension created by the combined actions of buoyancy force and magnetic field. This fluid pattern may display both Newtonian and non-Newtonian fluid properties. Continuity, temperature, motile microbe, momentum, and concentration equations are used in the mathematical formulation. The series solutions are found using the perturbation technique, and the leading parameters are described using graphs. Further, the impact of various physical constraints on different physiological quantities is addressed and illustrated through graphs and is pondered in detail. Bioconvection reduces the density of gyrotactic bacteria, according to the findings. Such findings are beneficial to biomedical sciences and engineering. Microorganisms are helpful in the breakdown of organic matter, the production of oxygen, and the maintenance of human health.

Influence of Bioconvection and Thermal Radiation on MHD Williamson Nano Casson Fluid Flow with the Swimming of Gyrotactic Microorganisms Due to Porous Stretching Sheet

An analysis is performed for electrical MHD flow of Williamson Nano Casson fluid with heat transfer. The fluid is positioned toward a porous stretching sheet along with mass flux. The impact of chemical diffusion and nonlinear thermal Radiation are further discussed. A highly nonlinear partial differential equations presenting the Williamson Nano Casson fluid flow over permeable extending plate is transformed to ordinary differential equations through appropriate similarity transformation and solved them with a shooting method-using package ND-Solve on Mathematica. The ascendency of arising physical interpretation of thermo-physical parameter on energy field, highly concentration field and density field are perceived. The valuations are achieved graphically for numerous protuberant terms like non Newtonian Williamson parameter, bio convection, Peclet number, mixed convection Hartman number, Casson parameter, thermophoresis diffusion, bio convection Rayeigh number, Brownian motion and mixed convection terms. These diverse terms are applied on dimensionless velocity function, concentration function, temperature function and density of the motile microorganism and analyzed numerically in detail. It is detected that through rising the value of bio-convection and Peclet number, the microorganism field diminishing. Graphical diagrams are illustrating the consistency of the latest outcomes.

Thermal Analysis of the Solar Collector Cum Storage System Using a Hybrid-Nanofluids

The main problem in the solar energy field is the storage of thermal energy. To divert this problem, it was suggested to use a flat-plat solar collector which also serves as a storage system; this solution will reduce the size of a refrigerating machine that we are studying. A high stored energy density is only possible if we through use latent heat of phase change. Thermal analysis has been developed for this type of storage collector for near-steady state conditions using a nanofluid heat storage substance depended on KNO3–NaNO3 binary salt mixture as PCM and a mix of Al2O3–SiO2 as nanoparticle, from which the new Hottel-Whillier-Bliss equations have been used for efficient flat plate collector. Computations were achieved for a large variety of parameters to verify the significance of the created model.

Slip Effects on a Ree-Eyring Liquid Peristaltic Flow Towards an Inclined Channel and Variable Liquid Properties

The current paper aims to model the flow of blood in narrow arteries by taking non-Newtonian Ree-Eyring fluid. The impact of wall properties, slip, mass, and heat transport are considered. In earlier studies, the viscosity of blood was considered a constant parameter. However, many researchers have claimed that the blood’s viscosity in the peripheral region is less than that of the core region. Thus, the present model incorporates the variation in thermal conductivity and viscosity, which takes a vital character in scrutinizing blood flow in narrow arteries. The mathematical model is developed on low Reynold’s number approximation and long wavelength, leading to the governing non-linear equations representing the flow phenomena. The governing non-linear partial differential equations are resolved by utilizing the series solution method (perturbation technique). MATLAB programming has been used to plot the pictorial representation of all the parameters through the flow quantities. The investigation shows that the variable velocity slip parameter and viscosity develops the velocity profiles. Further, the liquid parameter can be used to control the dimension of the trapped bolus. Moreover, the obtained outcomes aid in recognizing the flow of blood in micro arteries.

Channel flow of MHD bingham fluid due to peristalsis with multiple chemical reactions: an application to blood flow through narrow arteries

The present analysis emphasizes the effects of variable properties on Bingham fluid under MHD peristaltic transport. Due to the impact of mechanical forces on the applied magnetic field on the conducting fluid, the fluid stream gets altered. These principle targets drug transport and control of blood flow during surgeries; hence the impact of MHD flow with convective and porous boundary conditions is considered. Further, the implications of homogeneous and heterogeneous reactions are analyzed by considering wall properties. The governing equations are turned dimensionless by appropriate similarity transformations. The series solution is obtained for temperature, velocity, and concentration by perturbation method with lubrication approach. The graphical representation of the pertinent parameters on the physiological flow quantities is depicted by applying for MATLAB 2019b program. The obtained results reveal that the rise in the magnetic parameter diminishes the velocity and temperature profiles. Further, the impact of variable viscosity slightly improves the magnitude of the trapped bolus. The homogenous and heterogeneous reaction parameters have a converse effect on the concentration distribution. Moreover, the present investigation finds its applications to perceive the complex rheological functioning of blood flow through narrow arteries.

Aging-like Spontaneous Epigenetic Silencing Facilitates Wnt Activation, Stemness, and BrafV600E-Induced Tumorigenesis

We addressed the precursor role of aging-like spontaneous promoter DNA hypermethylation in initiating tumorigenesis. Using mouse colon-derived organoids, we show that promoter hypermethylation spontaneously arises in cells mimicking the human aging-like phenotype. The silenced genes activate the Wnt pathway, causing a stem-like state and differentiation defects. These changes render aged organoids profoundly more sensitive than young ones to transformation by BrafV600E, producing the typical human proximal BRAFV600E-driven colon adenocarcinomas characterized by extensive, abnormal gene-promoter CpG-island methylation, or the methylator phenotype (CIMP). Conversely, CRISPR-mediated simultaneous inactivation of a panel of the silenced genes markedly sensitizes to BrafV600E-induced transformation. Our studies tightly link aging-like epigenetic abnormalities to intestinal cell fate changes and predisposition to oncogene-driven colon tumorigenesis.

Breastmilk with a high omega-6 to omega-3 fatty acid ratio induced cellular events similar to insulin resistance and obesity in 3T3-L1 adipocytes

BACKGROUND

An imbalance of omega (n)-3 and n-6 polyunsaturated fatty acids (PUFA) during critical periods of development may have adverse effects on the health of the newborn in later life.

OBJECTIVES

We hypothesized that breastmilk with higher n-6 to n-3 PUFA ratio will have higher inflammatory cytokines and initiate cellular events similar to insulin resistance and obesity.

METHODS

Breastmilk was collected from healthy women who gave natural birth at full term. Breastmilk fatty acids were measured using gas chromatography; samples were pooled based on the n-6 to n-3 PUFA ratio (high, medium and low), and soluble cytokines were measured. Pooled samples were used to treat 3T3-L1 cells; mRNA expression of diacylglycerol acyltransferase2, stearoyl-CoA desaturase-1, leptin and RPLPO was measured.

RESULTS

Breastmilk with a higher ratio of n-6 to n-3 PUFA showed higher pro-inflammatory cytokines; there was a direct correlation between n-6 PUFA and pro-inflammatory cytokines. Breastmilk with a higher ratio of n-6 to n-3 PUFA increased the expression of genes involved in lipogenesis.

CONCLUSIONS

Pro-inflammatory cytokines in breastmilk are associated with higher levels of n-6 PUFA in breastmilk and has the capacity to alter adipose tissue metabolism to likely predispose the newborn to a higher risk of obesity in later life.

Inactivation of the WNT5A Alternative Promoter B Is Associated with DNA Methylation and Histone Modification in Osteosarcoma Cell Lines U2OS and SaOS-2

WNT5A is a secreted ligand involved in Wnt pathway signaling and has a role in cell movement and differentiation. Altered WNT5A expression is associated with various cancers, although in most studies the focus has been on only one of the known WNT5A isoforms. In this study, we analyzed expression from two of the major WNT5A promoters, termed promoter A and promoter B, in normal human osteoblasts, SaOS-2 and U2OS osteosarcoma cell lines, and osteosarcoma tumor tissue. We found that both promoters A and B are active in normal osteoblasts with nearly 11-fold more promoter B than A transcripts. Promoter B but not promoter A transcripts are decreased or nearly undetectable in the SaOS-2 and U2OS cell lines and osteosarcoma tumor tissues. Transient transfection of promoter A and promoter B reporter constructs confirmed that SaOS-2 cells have the necessary factors to transcribe both promoters. Bisulfite sequencing analysis revealed that three CpG enriched regions upstream of the promoter B exon 1βare highly methylated in both SaOS-2 and U2OS cells. The CpG island sub-region R6 located in promoter B exon 1β was approximately 51% methylated in SaOS-2 and 25% methylated in U2OS. Region 3 was approximately 28% methylated in normal osteoblasts, whereas the others were unmethylated. Promoter B was re-activated by treatment of SaOS-2 cells with 1 μM 5-azacytidine, which was associated with only a small insignificant change in methylation of sub-region R6. ChIP analysis of U2OS and SaOS-2 cells indicated that the promoter B region is less enriched in the active histone mark H3K4me3, in comparison to promoter A and that there is increased enrichment of the repressive mark H3K27me3 in association with the promoter B genomic region in the cell line SaOS-2. These findings show that epigenetic inactivation of the WNT5A promoter B involves both DNA methylation and histone modifications and suggest that differential expression of the WNT5A alternative promoters A and B is a characteristic of osteosarcomas.

Rare variants in tenascin genes in a cohort of children with primary vesicoureteric reflux

BACKGROUND

Primary vesicoureteral reflux (PVUR) is the most common malformation of the kidney and urinary tract, and reflux nephropathy is a major cause of chronic kidney disease in children. Recently, we reported mutations in the tenascin XB gene (TNXB) as a cause of PVUR with joint hypermobility.

METHODS

To define the role of rare variants in tenascin genes in the etiology of PVUR, we screened a cohort of patients with familial PVUR (FPVUR) and non-familial PVUR (NFPVUR) for rare missense variants inTNXB and the tenascin C gene (TNC) after excluding mutations in ROBO2 and SOX17.

RESULTS

The screening procedure identified 134 individuals from 112 families with PVUR; two families with mutations in ROBO2 were excluded from further analysis. Rare missense variants in TNXB were found in the remaining 110 families, of which 5/55 (9%) families had FPVUR and 2/55 (4%) had NFPVUR. There were no differences in high-grade reflux or renal parenchymal scarring between patients with and without TNXB variants. All patients with TNXB rare variants who were tested exhibited joint hypermobility. Overall we were able to identify causes of FPVUR in 7/57 (12%) families (9% in TNXB and 3% in ROBO2).

CONCLUSIONS

In conclusion, the identification of a rare missense variant in TNXB in combination with a positive family history of VUR and joint hypermobility may represent a non-invasive method to diagnose PVUR and warrants further evaluation in other cohorts.

Case of the month: Unusual presentation of myasthenia gravis with acute respiratory failure in the emergency room

A 21 year old woman with no past medical history presented to the emergency room (ER) with signs and symptoms of sepsis and subsequently went into acute respiratory failure. She was found to have myasthenia gravis which was exacerbated by the infection. This report highlights the need to consider myasthenia gravis in the differential diagnosis of an otherwise unexplained respiratory failure in the critical care setting.

Standardization of creatine kinase-MB (CK-MB) mass assays: the use of recombinant CK-MB as a reference material

BACKGROUND

The AACC assembled a committee to identify and validate a standard creatine kinase MB isoenzyme (CK-MB) material to improve the comparability of CK-MB mass assays.

METHODS

Three protocols were used. In protocol I, various CK-MB materials prepared in different matrices were screened as candidate standards. In protocol II, participating manufacturers calibrated their systems with concentrates of human heart CK-MB and then tested 20 patient samples to evaluate calibration bias. In protocol III, participating manufacturers calibrated their immunoassay systems using recombinant CK-MB2 (rCK-MB2) diluted into their respective sample diluents and measured 50 samples.

RESULTS

Candidate materials showed high recovery in stripped human serum, but bias improved only from 59% to 38%. These data led to the use of human heart CK-MB diluted in each manufacturer's sample diluent. This strategy reduced bias from 31% to 15%. Because human heart CK-MB is difficult to provide, a lyophilized source of CK-MB2 was identified. rCK-MB2 was shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, reversed-phase HPLC, intrinsic protein fluorescence, circular dichroism, agarose gel electrophoresis, immunoreactivity studies, high and low temperature stability, and reconstituted stability to be equivalent to human heart CK-MB. Calibration of immunoassay systems with rCK-MB2 added into each respective manufacturer's sample diluent showed a 13% between-manufacturer bias.

CONCLUSION

Lyophilized rCK-MB2 was determined suitable for use as a reference material for CK-MB mass assays.

Purification of five creatine kinase-MM variants from human heart and skeletal muscle

Variants of creatine kinase-MM (variant of ATP:creatine N-phosphotransferase, EC 2.7.3.2), present in human heart and skeletal muscle, have been purified to homogeneity using DEAE-Sepharose column chromatography and column chromatofocusing techniques. Creatine kinase-MM I-IV were present in both heart and skeletal muscle, while MM-V was found only in heart. The number, ratio and elution profile of the variants during chromatofocusing remained identical even when they were purified in the presence of proteinase inhibitors. MM-I-V, on chromatofocusing, were eluted at pH 8.3, 7.9, 7.6, 7.2 and 6.8, respectively. Isoelectric focusing revealed the pI of MM-I-V to be 7.2, 6.9, 6.7, 6.4 and 6.2. Sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis showed a doublet pattern for creatine kinase-MM variants III-V. However, polyacrylamide gel electrophoresis without SDS indicated homogeneity because each variant showed a single band. The doublet pattern observed in the presence of SDS may reflect the presence of two subunits of slightly different mass.