Identification of reference housekeeping-genes for mRNA expression studies in patients with type 1 diabetes

Cellular senescence molecules expression in type 2 diabetes mellitus: CDKN2A, CDKN2B, and lncRNA ANRIL

AIMS

Cellular senescence in type 2 diabetes mellitus (T2DM) has received widespread attention. However, the cellular senescence molecules involved in T2DM are unclear. Furthermore, there are no consistent biomarkers for cellular senescence in T2DM. Therefore, this study aimed to identify cellular senescence molecules in T2DM and investigate their expression in peripheral blood mononuclear cells of individuals with T2DM.

METHODS

Patients with T2DM (n = 40) and healthy controls (n = 40) were enrolled. We used different databases to identify cellular senescence molecules in T2DM and confirmed the obtained genes and lncRNA using real-time PCR.

RESULTS

Bioinformatics analysis indicated that CDKN2A and CDKN2B genes, and long noncoding RNA ANRIL are the most effective cellular senescence molecules in T2DM. Furthermore, CDKN2A and ANRIL expression decreased in individuals with T2DM.

CONCLUSIONS

Cellular senescence may have a protective effect against T2DM. In addition, the cellular senescence molecules CDKN2A and ANRIL may be potential biomarkers of cellular senescence in T2DM.

Identification of stable reference genes in peripheral blood mononuclear cells from type 2 diabetes mellitus patients

Reference genes are obligatory for accurate normalization of mRNA transcript levels across samples and experimental conditions in Real Time-polymerase chain reaction (qRT-PCR) based quantitative gene expression assays. Selection of stably expressed reference genes is therefore crucial for ensuring reproducibility of such assays. However, there is a complete dearth of data on stability of commonly used reference genes in Peripheral Blood Mononuclear Cells (PBMCs) from Type 2 diabetes mellitus (T2DM) patients. We have evaluated the gene expression stability of 4 widely used reference genes (Beta-actin, ACTB; Peptidylprolyl Isomerase B, PPIB; Tyrosine 3 Monooxygenase/Tryptophan 5-Monooxygenase Activation Protein Zeta, YWHAZ; and Glyceraldehyde-3-Phosphate Dehydrogenase, GAPDH); in PBMCs from 39 T2DM patients and 47 normoglycemic (NGT) subjects. ACTB and YWHAZ were found to be the most stable genes in PBMCs from T2DM patients and therefore, can be recommended as suitable reference genes in similar contexts. GAPDH and PPIB expressions were not stable in PBMCs from T2DM patients. On using ACTB and YWHAZ as reference genes for measuring relative expression of GAPDH and PPIB in these subjects, relative GAPDH expression was found to be significantly lower in female T2DM patients, compared to female NGT subjects [GAPDH relative normalization unit (RNU): female T2DM (n = 19), median (Q1, Q3): 9.0 (8.1, 9.9); female NGT (n = 18): median (Q1, Q3): 10.1 (9.1, 11.0); P = 0.034]. Dysregulation of GAPDH in PBMCs from female T2DM patients could be associated with sex-specific differences in pathogenesis and outcomes of T2DM.

Soluble PD-L1 in blood correlates positively with neutrophil and negatively with lymphocyte mRNA markers and implies adverse sepsis outcome

Sepsis causes a myriad of immunological reactions that result in life-threatening alterations in the human body. Immunosuppression in sepsis is partly attributed to the programmed death receptor (PD-1) and its associated ligand (PD-L1) via the regulation of lymphocytes and neutrophils. Although the soluble forms of these proteins (i.e., sPD-1 and sPD-L1, respectively) are recognized as possible sepsis biomarkers, their functional implications are yet to be elucidated. Our research assessed the correlation between sPD-1 and sPD-L1 and blood mRNA markers and sepsis outcome. Blood samples of septic patients of urogenital origin versus control patients (both groups: n = 18) were analyzed. Blood serum sPD-1 and sPD-L1 levels were determined using the enzyme-linked immunosorbent assay (ELISA). The whole blood mRNA concentrations of PD-1, PD-L1, neutrophil markers (CEACAM8 and MPO), and T-lymphocyte markers (TCRβ, CD4 and CD8) were determined via reverse transcriptase quantitative PCR (RT-qPCR). sPD-L1 levels were significantly increased in septic patients when compared to the controls, whereas sPD-1 levels were unaltered. Patients with high sPD-L1 levels, as dichotomized to the median, had a significantly shorter survival rate than those with low sPD-L1 levels. The sensitivity/specificity characteristics of sPD-L1 proved significant for sepsis detection. Furthermore, sPD-L1 correlated with the mRNA concentrations of PD-L1, CEACAM, and MPO, as well as major inflammatory markers (C-reactive protein and procalcitonin). However, sPD-L1 negatively correlated with TCRβ, CD4, and CD8 mRNAs. sPD-L1 was found to be significantly increased in septic patients. Notably, sPD-L1 correlated with PD-L1 mRNA and neutrophil markers and was indicative of adverse outcomes.

Osteogenic Mechanisms of Basal Ganglia Calcification and its ex vivo Model in the Hypoparathyroid Milieu

CONTEXT

Basal-ganglia calcification (BGC) is common (70%) in patients with chronic hypoparathyroidism. Interestingly, cortical gray matter is spared from calcification. The mechanism of BGC, role of hyperphosphatemia, and modulation of osteogenic molecules by parathyroid hormone (PTH) in its pathogenesis is not clear.

OBJECTIVE

We assessed the expression of a large repertoire of molecules with proosteogenic or antiosteogenic effects, including neuroprogenitor cells in caudate, dentate, and cortical gray matter from normal autopsy tissues. The effect of high phosphate and PTH was assessed in an ex vivo model of BGC using striatum tissue culture of the Sprague-Dawley rat.

METHODS

The messenger RNA and protein expression of 39 molecules involved in multiple osteogenic pathways were assessed in 25 autopsy tissues using reverse-transcriptase polymerase chain reaction, Western blot, and immunofluorescence. The striatal culture was maintained in a hypoparathyroid milieu for 24 days with and without (a) high phosphate (10-mm β-glycerophosphate) and (b) PTH(1-34) (50 ng/mL Dulbecco's modified Eagle's medium-F12 media) for their effect on striatal calcification and osteogenic molecules.

RESULTS

Procalcification molecules (osteonectin, β-catenin, klotho, FZD4, NT5E, LRP5, WNT3A, collagen-1α, and SOX2-positive neuroprogenitor stem cells) had significantly higher expression in the caudate than gray matter. Caudate nuclei also had higher expression of antiosteogenic molecules (osteopontin, carbonic anhydrase-II [CA-II], MGP, sclerostin, ISG15, ENPP1, and USP18). In an ex vivo model, striatum culture showed an increased propensity for calcified nodules with mineral deposition similar to that of bone tissue on Fourier-transformed infrared spectroscopy, alizarin, and von Kossa stain. Mineralization in striatal culture was enhanced by high phosphate and decreased by exogenous PTH through increased expression of CA-II.

CONCLUSION

This study provides a conceptual advance on the molecular mechanisms of BGC and the possibility of PTH therapy to prevent this complication in a hypoparathyroid milieu.

Selection of reliable reference genes for analysis of gene expression in the rat placenta

The selection of suitable reference genes (RGs), especially the identification of the proper combination of RGs is the key to obtain reliable results of gene expression for quantitative real-time polymerase chain reaction (qRT-PCR). To date, there is no relevant study dealing with the stability of RGs in rat placenta. In this study, the geNorm, NormFinder, and BestKeeper software were used to analyze the expression stability of the candidate RGs in placenta under physiological and prenatal caffeine exposure (PCE) conditions. The expression of Tbp, Gapdh and Ywhaz in female and Polr2a, Gapdh and Ywhaz in male placenta were highly stable under physiological conditions, and there was no obvious gender difference. We further found that two RGs were sufficient for reliable normalization in female and male placenta and the combination of Ywhaz and Gapdh was the most suitable compound RGs under physiological conditions. Under PCE conditions, Ywhaz, Gapdh and Polr2a were the most stable genes in both female and male placenta. Among them, Ywhaz and Gapdh were chosen as the best paring. Finally, selected RGs were employed for normalization of the expression of a clear target gene and the results of standardization supported our choice. In conclusion, our study confirmed that Ywhaz/Gapdh combination was the most suitable RGs in rat placenta under physiological and PCE pathological conditions and provided a theoretical and experimental basis for physiological and pathological research of the rat placenta.

Identification of suitable mRNAs and microRNAs as reference genes for expression analyses in skin cells under sex hormone exposure

Quantitative RT-PCR is the most accurate technique for the study of gene expression profiles, however, to ensure the accuracy of qPCR results, suitable reference genes are necessary for data normalization. Hormones influence the development and function of skin cells, regulating the expression of genes and miRNAs. Nevertheless, the stability of reference genes after sex hormone treatment has not been thoroughly investigated. In this study, we evaluated the expression of a set of candidate mRNAs and microRNsA (miRNA) as reference genes in keratinocytes (HaCaT cells), primary human fibroblasts and a melanoma cell line (LM-36 cells) under testosterone or 17β-estradiol treatment. Two algorithms, namely geNorm, Best-Keeper, and the comparative ΔCt method were used to evaluate the expression stability of the candidate reference genes. The comprehensive ranking showed that TBP and miR-191-5p are the most stable expressed genes across all cultured cells under hormone treatment. Furthermore, we observed that GAPDH, HPRT1 and U6 snRNA expression may be altered by hormone exposure, thus, these genes are not recommended as reference genes. In conclusion, the present study provides, to the best of our knowledge, the first evaluation of expressed mRNA(s) and miRNA(s) as reference genes in three different types of skin cells under the stimulation of sex hormones.

Decreased placental apoptosis and autophagy in pregnancies complicated by gestational diabetes with large-for-gestational age fetuses

INTRODUCTION

Dysregulation of placental apoptosis and autophagy are observed in pregnancy complications including preeclampsia and fetal growth restriction. However, studies of their changes in the placentas of women with gestational diabetes mellitus (GDM) show inconsistent results. We aimed to compare the changes in apoptosis, autophagy, and Bcl-2 family proteins in the placentas from women with normal pregnancies and those with GDM, with or without large-for-gestational age (LGA) infants and to investigate the effect of hyperglycemia on the changes in apoptosis, autophagy, and Bcl-2 family proteins in primary cytotrophoblastic cells.

METHODS

Villous tissues were obtained from normal pregnant women and those with GDM, with or without LGA infants. Primary cytotrophoblast cells were isolated from normal term placentas and cultured under standard, hyperglycemic, or hyperosmotic conditions.

RESULTS

Compared to placentas from normal pregnant women, those from GDM women with LGA infants were heavier, had lower beclin-1 and DRAM levels, less M30 and cleaved PARP immunoreactivity, and increased Ki-67 immunoreactivity. These changes were associated with increased Bcl-xL and decreased Bak levels. Increased glucose concentration led to lower ATG5, beclin-1, LC3B-II, p62, and DRAM levels, lower annexin V and M30-positive cell percentages, and less cleaved PARP changes compared with standard culture conditions. Hyperglycemia caused higher Bcl-xL levels and lower Bak and Bad levels than did standard culture conditions.

DISCUSSION

There were differential changes in apoptosis and autophagy between placentas from normal pregnant women and those from GDM women with LGA infants. Bcl-2 family proteins are likely involved in the regulation of these changes.

Effects of diabetes mellitus on myenteric neuronal density and sodium channel expression in the rat ileum

Diabetes mellitus (DM) may lead to gastrointestinal motility disorders. Rodent models of DM indicate the presence of morpho-functional abnormalities of the enteric nervous system. Here, we evaluated whether experimental DM can cause changes in the excitatory cholinergic fibers, neuronal density, and voltage-gated sodium channel (Nav) expression in the myenteric plexus of the ileum. After streptozotocin-induced hyperglycemia in female rats progressed for eight weeks, triple immunofluorescence labeling experiments revealed that the neuronal density in DM rats was significantly lower than that in control. On average, the density of total neurons reduced by 52.2% (p = 0.0001), cholinergic neurons by 50.0% (p = 0.0068), and nitrergic neurons by 54.8% (p = 0.0042). The number of neurons per ganglionic area was also significantly reduced (to 28.2% of total neurons, p = 0.0002; 27.7% of cholinergic neurons, p = 0.0002, and 32.1% of nitrergic neurons, p = 0.0016). Furthermore, the density of the cholinergic fibers at the surface of the longitudinal muscle was significantly reduced (DM: 24 ± 3%; p = 0.003, control: 41 ± 2%); however, western-blot analysis did not indicate a reduction in the expression of choline acetyltransferase (ChAT) in the DM group. The Nav1.6 isoform was detected in different myenteric neurons of the ileum. RT-qPCR data did not suggest an alteration of transcripts for ChAT, neuronal nitric oxide synthase, Nav1.3, Nav1.6, or Nav1.7. Our data support the view that chronic DM leads to a reduction of excitatory cholinergic fibers and neuronal density. However, changes in sodium channel expression pattern, which could cause neuronal dysfunction, were not detected.

Measurement and Clinical Significance of Biomarkers of Oxidative Stress in Humans

Oxidative stress is the result of the imbalance between reactive oxygen species (ROS) formation and enzymatic and nonenzymatic antioxidants. Biomarkers of oxidative stress are relevant in the evaluation of the disease status and of the health-enhancing effects of antioxidants. We aim to discuss the major methodological bias of methods used for the evaluation of oxidative stress in humans. There is a lack of consensus concerning the validation, standardization, and reproducibility of methods for the measurement of the following: (1) ROS in leukocytes and platelets by flow cytometry, (2) markers based on ROS-induced modifications of lipids, DNA, and proteins, (3) enzymatic players of redox status, and (4) total antioxidant capacity of human body fluids. It has been suggested that the bias of each method could be overcome by using indexes of oxidative stress that include more than one marker. However, the choice of the markers considered in the global index should be dictated by the aim of the study and its design, as well as by the clinical relevance in the selected subjects. In conclusion, the clinical significance of biomarkers of oxidative stress in humans must come from a critical analysis of the markers that should give an overall index of redox status in particular conditions.