Analysis of polymorphism and hepatic expression of duodenal cytochrome b in chronic hepatitis C.

BACKGROUND AND AIM: Pathological iron overload is commonly found in chronic hepatitis C (CHC) patients and considered as a negative prognostic factor of the disease. A single nucleotide polymorphism (SNP) rs884409 in duodenal cytochrome b gene (CYBRD1) is implicated in the pathogenesis of hemochromatosis. In our study we investigated the impact of the CYBRD1 genotype and expression on iron overload in CHC patients. METHODS: Liver biopsy specimens and whole blood samples from 243 patients with CHC were included in the study. Iron deposits in hepatocytes, serum markers of iron overload, and expression profile of gene-regulators of iron homeostasis were analyzed. Genotyping and analysis of gene expression of the CYBRD1 were performed. The frequency of SNP and the expression levels of CYBRD1 were compared between the groups of patients with and without markers of iron overload. RESULTS: The single nucleotide variant rs884409 G was associated with elevated serum iron levels, increased markers of liver inflammation, and oxidative stress. Hepatic expression of CYBRD1 was associated with the expression of Tfr2, Id1, and HO-1 genes, serum ferritin levels, and with increased iron accumulation in liver. CONCLUSION: These results implicate CYBRD1 involvement in iron homeostasis in CHC.

Molecular pathogenesis and clinical consequences of iron overload in liver cirrhosis.

BACKGROUND: The liver, as the main iron storage compartment and the place of hepcidin synthesis, is the central organ involved in maintaining iron homeostasis in the body. Excessive accumulation of iron is an important risk factor in liver disease progression to cirrhosis and hepatocellular carcinoma. Here, we review the literature on the molecular pathogenesis of iron overload and its clinical consequences in chronic liver diseases. DATA SOURCES: PubMed was searched for English-language articles on molecular genesis of primary and secondary iron overload, as well as on their association with liver disease progression. We have also included literature on adjuvant therapeutic interventions aiming to alleviate detrimental effects of excessive body iron load in liver cirrhosis. RESULTS: Excess of free, unbound iron induces oxidative stress, increases cell sensitivity to other detrimental factors, and can directly affect cellular signaling pathways, resulting in accelerated liver disease progression. Diagnosis of liver cirrhosis is, in turn, often associated with the identification of a pathological accumulation of iron, even in the absence of genetic background of hereditary hemochromatosis. Iron depletion and adjuvant therapy with antioxidants are shown to cause significant improvement of liver functions in patients with iron overload. Phlebotomy can have beneficial effects on liver histology in patients with excessive iron accumulation combined with compensated liver cirrhosis of different etiology. CONCLUSION: Excessive accumulation of body iron in liver cirrhosis is an important predictor of liver failure and available data suggest that it can be considered as target for adjuvant therapy in this condition.

Improving the treatment of bacterial infections caused by multidrug-resistant bacteria through drug repositioning.

Drug repurposing (repositioning) is a dynamically-developing area in the search for effective therapy of infectious diseases. Repositioning existing drugs with a well-known pharmacological and toxicological profile is an attractive method for quickly discovering new therapeutic indications. The off-label use of drugs for infectious diseases requires much less capital and time, and can hasten progress in the development of new antimicrobial drugs, including antibiotics. The use of drug repositioning in searching for new therapeutic options has brought promising results for many viral infectious diseases, such as Ebola, ZIKA, Dengue, and HCV. This review describes the most favorable results for repositioned drugs for the treatment of bacterial infections. It comprises publications from various databases including PubMed and Web of Science published from 2015 to 2023. The following search keywords/strings were used: drug repositioning and/or repurposing and/or antibacterial activity and/or infectious diseases. Treatment options for infections caused by multidrug-resistant bacteria were taken into account, including methicillin-resistant staphylococci, multidrug-resistant Mycobacterium tuberculosis, or carbapenem-resistant bacteria from the Enterobacteriaceae family. It analyses the safety profiles of the included drugs and their synergistic combinations with antibiotics and discusses the potential of antibacterial drugs with antiparasitic, anticancer, antipsychotic effects, and those used in metabolic diseases. Drug repositioning may be an effective response to public health threats related to the spread of multidrug-resistant bacterial strains and the growing antibiotic resistance of microorganisms.

Transgenic rhesus monkeys produced by gene transfer into early-cleavage-stage embryos using a simian immunodeficiency virus-based vector.

The development of transgenic technologies in monkeys is important for creating valuable animal models of human physiology so that the etiology of diseases can be studied and potential therapies for their amelioration may be developed. However, the efficiency of producing transgenic primate animals is presently very low, and there are few reports of success. We have developed an improved methodology for the production of transgenic rhesus monkeys, making use of a simian immunodeficiency virus (SIV)-based vector that encodes EGFP and a protocol for infection of early-cleavage-stage embryos. We show that infection does not alter embryo development. Moreover, the timing of infection, either before or during embryonic genome activation, has no observable effect on the level and stability of transgene expression. Of 70 embryos injected with concentrated virus at the one- to two-cell stage or the four- to eight-cell stage and showing fluorescence, 30 were transferred to surrogate mothers. One transgenic fetus was obtained from a fraternal triple pregnancy. Four infant monkeys were produced from four singleton pregnancies, of which two expressed EGFP throughout the whole body. These results demonstrate the usefulness of SIV-based lentiviral vectors for the generation of transgenic monkeys and improve the efficiency of transgenic technology in nonhuman primates.

Induced Cognitive Impairments Reversed by Grafts of Neural Precursors: A Longitudinal Study in a Macaque Model of Parkinson's Disease.

Parkinson's disease (PD) evolves over an extended and variable period in humans; years prior to the onset of classical motor symptoms, sleep and biological rhythm disorders develop, significantly impacting the quality-of-life of patients. Circadian-rhythm disorders are accompanied by mild cognitive deficits that progressively worsen with disease progression and can constitute a severe burden for patients at later stages. The gold-standard 6-methyl-1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin (MPTP) macaque model of PD recapitulates the progression of motor and nonmotor symptoms over contracted periods of time. Here, this multidisciplinary/multiparametric study follows, in five animals, the steady progression of motor and nonmotor symptoms and describes their reversal following grafts of neural precursors in diverse functional domains of the basal ganglia. Results show unprecedented recovery from cognitive symptoms in addition to a strong clinical motor recuperation. Both motor and cognitive recovery and partial circadian rhythm recovery correlate with the degree of graft integration, and in a subset of animals, with in vivo levels of striatal dopaminergic innervation and function. The present study provides empirical evidence that integration of neural precursors following transplantation efficiently restores function at multiple levels in parkinsonian nonhuman primates and, given interindividuality of disease progression and recovery, underlines the importance of longitudinal multidisciplinary assessments in view of clinical translation.

Introduction of Mouse Embryonic Fibroblasts into Early Embryos: From Confusion to Constructive Discussion. Comment on Savatier, P. Introduction of Mouse Embryonic Fibroblasts into Early Embryos Causes Reprogramming and (Con)fusion. Cells 2021, 10, 772.

We would like to address the issues raised by Pierre Savatier in "Introduction of Mouse Embryonic Fibroblasts into Early Embryos Causes Reprogramming and (Con)Fusion" [...].

Embryonic Environmental Niche Reprograms Somatic Cells to Express Pluripotency Markers and Participate in Adult Chimaeras.

The phenomenon of the reprogramming of terminally differentiated cells can be achieved by various means, like somatic cell nuclear transfer, cell fusion with a pluripotent cell, or the introduction of pluripotency genes. Here, we present the evidence that somatic cells can attain the expression of pluripotency markers after their introduction into early embryos. Mouse embryonic fibroblasts introduced between blastomeres of cleaving embryos, within two days of in vitro culture, express transcription factors specific to blastocyst lineages, including pluripotency factors. Analysis of donor tissue marker DNA has revealed that the progeny of introduced cells are found in somatic tissues of foetuses and adult chimaeras, providing evidence for cell reprogramming. Analysis of ploidy has shown that in the chimaeras, the progeny of introduced cells are either diploid or tetraploid, the latter indicating cell fusion. The presence of donor DNA in diploid cells from chimaeric embryos proved that the non-fused progeny of introduced fibroblasts persisted in chimaeras, which is evidence of reprogramming by embryonic niche. When adult somatic (cumulus) cells were introduced into early cleavage embryos, the extent of integration was limited and only cell fusion-mediated reprogramming was observed. These results show that both cell fusion and cell interactions with the embryonic niche reprogrammed somatic cells towards pluripotency.

Derivation and cloning of a novel rhesus embryonic stem cell line stably expressing tau-green fluorescent protein.

Embryonic stem cells (ESC) have the ability of indefinite self-renewal and multilineage differentiation, and they carry great potential in cell-based therapies. The rhesus macaque is the most relevant preclinical model for assessing the benefit, safety, and efficacy of ESC-based transplantations in the treatment of neurodegenerative diseases. In the case of neural cell grafting, tracing both the neurons and their axonal projections in vivo is essential for studying the integration of the grafted cells in the host brain. Tau-Green fluorescent protein (tau-GFP) is a powerful viable lineage tracer, allowing visualization of cell bodies, dendrites, and axons in exquisite detail. Here, we report the first rhesus monkey ESC line that ubiquitously and stably expresses tau-GFP. First, we derived a new line of rhesus monkey ESC (LYON-ES1) that show marker expression and cell cycle characteristics typical of primate ESCs. LYON-ES1 cells are pluripotent, giving rise to derivatives of the three germ layers in vitro and in vivo through teratoma formation. They retain all their undifferentiated characteristics and a normal karyotype after prolonged culture. Using lentiviral infection, we then generated a monkey ESC line stably expressing tau-GFP that retains all the characteristics of the parental wild-type line and is clonogenic. We show that neural precursors derived from the tau-GFP ESC line are multipotent and that their fate can be precisely mapped in vivo after grafting in the adult rat brain. Disclosure of potential conflicts of interest is found at the end of this article.

Rose Bengal-Mediated Photoinactivation of Multidrug Resistant Pseudomonas aeruginosa Is Enhanced in the Presence of Antimicrobial Peptides.

Due to the overuse of antibiotics in medicine and food production, and their targeted mechanism of action, an increasing rate in spreading of antibiotic resistance genes has been noticed. This results in inefficient therapy outcomes and higher mortality all over the world. Pseudomonas aeruginosa (carbapenem-resistant) is considered one of the top three critical species according to the World Health Organization's priority pathogens list. This means that new drugs and/or treatments are needed to tackle infections caused by this bacterium. In this context search for new/alternative approaches that would overcome resistance to classical antimicrobials is of prime importance. The use of antimicrobial photodynamic inactivation (aPDI) and antimicrobial peptides (AMPs) is an efficient strategy to treat localized infections caused by multidrug-resistant P. aeruginosa. In this study, we have treated P. aeruginosa cells photodynamically in the presence and in the absence of AMP (CAMEL or pexiganan). The conditions for aPDI were as follows: rose bengal (RB) as a photosensitizing agent at 1-10 µM concentration, and subsequent irradiation with 514 nm-LED at 23 mW/cm2 irradiance. The analysis of cell number after the treatment has shown that the combined action of RB-mediated aPDI and cationic AMPs reduced the number of viable cells below the limit of detection (<1log10 CFU/ml). This was in contrast to no reduction or partial reduction after aPDI or AMP applied separately. Students t-test was applied to test the statistical significance of the results. Noteworthy, our treatment proved to be effective against all 35 clinical isolates of P. aeruginosa tested within this study, including those characterized as multiresistant. Moreover, we demonstrated that such treatment is safe and does not violate the growth dynamics of human keratinocytes (77.3-97.64% survival depending on the concentration of the studied compounds or their mixtures).

Interferon lambda polymorphisms associate with body iron indices and hepatic expression of interferon-responsive long non-coding RNA in chronic hepatitis C.

Single nucleotide polymorphisms (SNPs) within DNA region containing interferon lambda 3 (IFNL3) and IFNL4 genes are prognostic factors of treatment response in chronic hepatitis C (CHC). Iron overload, frequently diagnosed in CHC, is associated with unfavorable disease course and a risk of carcinogenesis. Its etiology and relationship with the immune response in CHC are not fully explained. Our aim was to determine whether IFNL polymorphisms in CHC patients associate with body iron indices, and whether they are linked with hepatic expression of genes involved in iron homeostasis and IFN signaling. For 192 CHC patients, four SNPs within IFNL3-IFNL4 region (rs12979860, rs368234815, rs8099917, rs12980275) were genotyped. In 185 liver biopsies, histopathological analyses were performed. Expression of five mRNAs and three long non-coding RNAs (lncRNAs) was determined with qRT-PCR in 105 liver samples. Rs12979860 TT or rs8099917 GG genotypes as well as markers of serum and hepatocyte iron overload associated with higher activity of gamma-glutamyl transpeptidase and liver steatosis. The presence of two minor alleles in any of the tested SNPs predisposed to abnormally high serum iron concentration and correlated with higher hepatic expression of lncRNA NRIR. On the other hand, homozygosity in any major allele associated with higher viral load. Patients bearing rs12979860 CC genotype had lower hepatic expression of hepcidin (HAMP; P = 0.03). HAMP mRNA level positively correlated with serum iron indices and degree of hepatocyte iron deposits. IFNL polymorphisms influence regulatory pathways of cellular response to IFN and affect body iron balance in chronic hepatitis C virus infection.

Interaction between the HPV E7 oncoprotein and the transcriptional coactivator p300.

Infection with high-risk human papillomaviruses (HPV) can lead to the development of cervical cancer. This process depends on the interaction of the virus-encoded oncoproteins, E6 and E7, with a variety of host regulatory proteins. As E7 shares both functional and structural similarities with the Adenovirus E1a (Ad E1a) protein, we were interested in investigating the possible interactions between E7 and the transcriptional coactivator p300, since it was originally identified as a target of Ad E1a. Using a variety of assays, we show that E7s from both high- and low-risk HPV types interact with p300. Mutational analysis of E7 maps the site of the interaction to a region spanning the pRb-binding domain and the CKII phosphorylation site. We also map the site of interaction on p300 largely to the CH1 domain. In addition, we demonstrate that the binding between 16E7 and p300 is direct, and can be detected in vivo by coimmunoprecipitation and mammalian two-hybrid assays. Finally, we show that E7 can abolish the p300-mediated E2 transactivation function, suggesting that complex formation between E7 and p300 may contribute to the regulation of E2 transcriptional activity.

A short G1 phase is an intrinsic determinant of naïve embryonic stem cell pluripotency.

A short G1 phase is a characteristic feature of mouse embryonic stem cells (ESCs). To determine if there is a causal relationship between G1 phase restriction and pluripotency, we made use of the Fluorescence Ubiquitination Cell Cycle Indicator (FUCCI) reporter system to FACS-sort ESCs in the different cell cycle phases. Hence, the G1 phase cells appeared to be more susceptible to differentiation, particularly when ESCs self-renewed in the naïve state of pluripotency. Transitions from ground to naïve, then from naïve to primed states of pluripotency were associated with increased durations of the G1 phase, and cyclin E-mediated alteration of the G1/S transition altered the balance between self-renewal and differentiation. LIF withdrawal resulted in a lengthening of the G1 phase in naïve ESCs, which occurred prior to the appearance of early lineage-specific markers, and could be reversed upon LIF supplementation. We concluded that the short G1 phase observed in murine ESCs was a determinant of naïve pluripotency and was partially under the control of LIF signaling.

Induced pluripotent stem cells derived from rabbits exhibit some characteristics of naïve pluripotency.

Not much is known about the molecular and functional features of pluripotent stem cells (PSCs) in rabbits. To address this, we derived and characterized 2 types of rabbit PSCs from the same breed of New Zealand White rabbits: 4 lines of embryonic stem cells (rbESCs), and 3 lines of induced PSCs (rbiPSCs) that were obtained by reprogramming adult skin fibroblasts. All cell lines required fibroblast growth factor 2 for their growth and proliferation. All rbESC lines showed molecular and functional properties typically associated with primed pluripotency. The cell cycle of rbESCs had a prolonged G1 phase and a DNA damage checkpoint before entry into the S phase, which are the 2 features typically associated with the somatic cell cycle. In contrast, the rbiPSC lines exhibited some characteristics of naïve pluripotency, including resistance to single-cell dissociation by trypsin, robust activity of the distal enhancer of the mouse Oct4 gene, and expression of naïve pluripotency-specific genes, as defined in rodents. According to gene expression profiles, rbiPSCs were closer to the rabbit inner cell mass (ICM) than rbESCs. Furthermore, rbiPSCs were capable of colonizing the ICM after aggregation with morulas. Therefore, we propose that rbiPSCs self-renew in an intermediate state between naïve and primed pluripotency, which represents a key step toward the generation of bona fide naïve PSC lines in rabbits.

Forced expression of LIM homeodomain transcription factor 1b enhances differentiation of mouse embryonic stem cells into serotonergic neurons.

The LIM homeodomain transcription factor 1b (Lmx1b) is a key factor in the specification of the serotonergic neurotransmitter phenotype. Here, we explored the capacity of Lmx1b to direct differentiation of mouse embryonic stem (mES) cells into serotonergic neurons. mES cells stably expressing human Lmx1b were generated by lentiviral vector infection. Clones expressing Lmx1b at a low level showed increased neurogenesis and elevated production of neurons expressing serotonin, serotonin transporter, tryptophan hydroxylase 2, and transcription factor Pet1, the landmarks of serotonergic differentiation. To explore the role of Lmx1b in the specification of the serotonin neurotransmission phenotype further, a conditional system making use of a floxed inducible vector targeted into the ROSA26 locus and a hormone-dependent Cre recombinase was engineered. This novel strategy was tested with the reporter gene encoding human placental alkaline phosphatase, and demonstrated its capacity to drive transgene expression in nestin(+) neural progenitors (NPs) and in Tuj1(+) neurons. When it was applied to inducible expression of human Lmx1b, it resulted in elevated expression of serotonergic markers. Treatment of neural precursors with the floor plate signal Sonic hedgehog further enhanced differentiation of Lmx1b-overexpressing NPs into neurons expressing 5-HT, serotonin transporter, tryptophan hydroxylase 2, and Pet1, when compared with Lmx1b-nonexpressing progenitors. Together, our results demonstrate the capacity of Lmx1b to specify a serotonin neurotransmitter phenotype when overexpressed in mES cell-derived NPs.

Complementation of a p300/CBP defective-binding mutant of adenovirus E1a by human papillomavirus E6 proteins.

Previous studies have shown that the human papillomavirus type 16 (HPV-16) E6 protein binds to p300/CBP and abrogates its transcriptional co-activator function. However, there is little information on the biological consequences of this interaction and discrepancy as to whether the interaction is high-risk E6 specific or not. We performed a series of studies to compare the interactions of HPV-18 and HPV-11 E6 with p300, and showed that both high- and low- risk E6 proteins bind p300. In addition, using a transformation-deficient mutant of adenovirus E1a, which cannot interact with p300, we demonstrated that HPV-16, HPV-18 and, to a lesser extent, HPV-11 E6, can complement this mutant in cell transformation assays. In contrast, a mutant of HPV-16 E6 which does not bind p300 failed to rescue the E1a mutant. These results suggest that the E6-p300 interaction may be important for the ability of HPV E6 to contribute towards cell transformation.

Comparative analysis of the intracellular location of the high- and low-risk human papillomavirus oncoproteins.

We have compared the intracellular location of the HPV E6 and E7 proteins from high- and low-risk virus types. While high-risk HPV E7 displays diffuse nuclear expression, low-risk E7 has a nuclear punctuate pattern of expression. Similarly, while high-risk E6 is expressed throughout the cell, low-risk E6 is again predominantly nuclear with a punctuate pattern of expression. Both low-risk viral oncoproteins show colocalization with PML, whereas high-risk viral proteins do not. Finally, inhibition of the proteasome pathway results in a dramatic nuclear accumulation of high-risk E6 protein. These results demonstrate fundamental differences in the localization of these viral oncoproteins within the cell and offer alternative explanations for their respective differences in pathology.