Gene Expression Profiling Reveals Fundamental Sex-Specific Differences in SIRT3-Mediated Redox and Metabolic Signaling in Mouse Embryonic Fibroblasts.

Sirt-3 is an important regulator of mitochondrial function and cellular energy homeostasis, whose function is associated with aging and various pathologies such as Alzheimer's disease, Parkinson's disease, cardiovascular diseases, and cancers. Many of these conditions show differences in incidence, onset, and progression between the sexes. In search of hormone-independent, sex-specific roles of Sirt-3, we performed mRNA sequencing in male and female Sirt-3 WT and KO mouse embryonic fibroblasts (MEFs). The aim of this study was to investigate the sex-specific cellular responses to the loss of Sirt-3. By comparing WT and KO MEF of both sexes, the differences in global gene expression patterns as well as in metabolic and stress responses associated with the loss of Sirt-3 have been elucidated. Significant differences in the activities of basal metabolic pathways were found both between genotypes and between sexes. In-depth pathway analysis of metabolic pathways revealed several important sex-specific phenomena. Male cells mount an adaptive Hif-1a response, shifting their metabolism toward glycolysis and energy production from fatty acids. Furthermore, the loss of Sirt-3 in male MEFs leads to mitochondrial and endoplasmic reticulum stress. Since Sirt-3 knock-out is permanent, male cells are forced to function in a state of persistent oxidative and metabolic stress. Female MEFs are able to at least partially compensate for the loss of Sirt-3 by a higher expression of antioxidant enzymes. The activation of neither Hif-1a, mitochondrial stress response, nor oxidative stress response was observed in female cells lacking Sirt-3. These findings emphasize the sex-specific role of Sirt-3, which should be considered in future research.

ICTV Virus Taxonomy Profile: Adenoviridae 2022.

The family Adenoviridae includes non-enveloped viruses with linear dsDNA genomes of 25-48 kb and medium-sized icosahedral capsids. Adenoviruses have been discovered in vertebrates from fish to humans. The family is divided into six genera, each of which is more common in certain animal groups. The outcome of infection may vary from subclinical to lethal disease. This is a summary of the ICTV Report on the family Adenoviridae, which is available at ictv.global/report/adenoviridae.

Ancient Origins of Cytoskeletal Crosstalk: Spectraplakin-like Proteins Precede the Emergence of Cortical Microtubule Stabilization Complexes as Crosslinkers.

Adhesion between cells and the extracellular matrix (ECM) is one of the prerequisites for multicellularity, motility, and tissue specialization. Focal adhesions (FAs) are defined as protein complexes that mediate signals from the ECM to major components of the cytoskeleton (microtubules, actin, and intermediate filaments), and their mutual communication determines a variety of cellular processes. In this study, human cytoskeletal crosstalk proteins were identified by comparing datasets with experimentally determined cytoskeletal proteins. The spectraplakin dystonin was the only protein found in all datasets. Other proteins (FAK, RAC1, septin 9, MISP, and ezrin) were detected at the intersections of FAs, microtubules, and actin cytoskeleton. Homology searches for human crosstalk proteins as queries were performed against a predefined dataset of proteomes. This analysis highlighted the importance of FA communication with the actin and microtubule cytoskeleton, as these crosstalk proteins exhibit the highest degree of evolutionary conservation. Finally, phylogenetic analyses elucidated the early evolutionary history of spectraplakins and cortical microtubule stabilization complexes (CMSCs) as model representatives of the human cytoskeletal crosstalk. While spectraplakins probably arose at the onset of opisthokont evolution, the crosstalk between FAs and microtubules is associated with the emergence of metazoans. The multiprotein complexes contributing to cytoskeletal crosstalk in animals gradually gained in complexity from the onset of metazoan evolution.

Polysialic acid is a cellular receptor for human adenovirus 52.

Human adenovirus 52 (HAdV-52) is one of only three known HAdVs equipped with both a long and a short fiber protein. While the long fiber binds to the coxsackie and adenovirus receptor, the function of the short fiber in the virus life cycle is poorly understood. Here, we show, by glycan microarray analysis and cellular studies, that the short fiber knob (SFK) of HAdV-52 recognizes long chains of α-2,8-linked polysialic acid (polySia), a large posttranslational modification of selected carrier proteins, and that HAdV-52 can use polySia as a receptor on target cells. X-ray crystallography, NMR, molecular dynamics simulation, and structure-guided mutagenesis of the SFK reveal that the nonreducing, terminal sialic acid of polySia engages the protein with direct contacts, and that specificity for polySia is achieved through subtle, transient electrostatic interactions with additional sialic acid residues. In this study, we present a previously unrecognized role for polySia as a cellular receptor for a human viral pathogen. Our detailed analysis of the determinants of specificity for this interaction has general implications for protein-carbohydrate interactions, particularly concerning highly charged glycan structures, and provides interesting dimensions on the biology and evolution of members of Human mastadenovirus G.

Chronic High Fat Diet Intake Impairs Hepatic Metabolic Parameters in Ovariectomized Sirt3 KO Mice.

High fat diet (HFD) is an important factor in the development of metabolic diseases, with liver as metabolic center being highly exposed to its influence. However, the effect of HFD-induced metabolic stress with respect to ovary hormone depletion and sirtuin 3 (Sirt3) is not clear. Here we investigated the effect of Sirt3 in liver of ovariectomized and sham female mice upon 10 weeks of feeding with standard-fat diet (SFD) or HFD. Liver was examined by Folch, gas chromatography and lipid hydroperoxide analysis, histology and oil red staining, RT-PCR, Western blot, antioxidative enzyme and oxygen consumption analyses. In SFD-fed WT mice, ovariectomy increased Sirt3 and fatty acids synthesis, maintained mitochondrial function, and decreased levels of lipid hydroperoxides. Combination of ovariectomy and Sirt3 depletion reduced pparα, Scd-1 ratio, MUFA proportions, CII-driven respiration, and increased lipid damage. HFD compromised CII-driven respiration and activated peroxisomal ROS scavenging enzyme catalase in sham mice, whereas in combination with ovariectomy and Sirt3 depletion, increased body weight gain, expression of NAFLD- and oxidative stress-inducing genes, and impaired response of antioxidative system. Overall, this study provides evidence that protection against harmful effects of HFD in female mice is attributed to the combined effect of female sex hormones and Sirt3, thus contributing to preclinical research on possible sex-related therapeutic agents for metabolic syndrome and associated diseases.

Adenoviruses of the most ancient primate lineages support the theory on virus-host co-evolution.

The scarcity or complete lack of information on the adenoviruses (AdVs) occurring in the most ancient non-human primates resulted in the initiation of a study for exploring their abundance and diversity in prosimians and New World monkeys (NWMs). In order to assess the variability of these AdVs and the possible signs of the hypothesised virus-host co-evolution, samples from almost every family of NWMs and prosimians were screened for the presence of AdVs. A PCRscreening of 171 faecal or organ samples from live or dead, captive or wild-living prosimians and NWMs was performed. The PCR products from the gene of the IVa2 protein were sequenced and used in phylogeny calculations. The presence of 10 and 15 new AdVs in seven and ten different species of prosimians and NWMs was revealed, respectively. Phylogenetic analysis indicated that the tentative novel AdVs cluster into two separate groups, which form the most basal branches among the primate AdVs, and therefore support the theory on the co-evolution of primate AdVs with their hosts. This is the first report that provides a comprehensive overview of the AdVs occurring in prosimians and NWMs, and the first insight into the evolutionary relationships among AdVs from all major primate groups.

Genome analysis of four Old World monkey adenoviruses supports the proposed species classification of primate adenoviruses and reveals signs of possible homologous recombination.

Within the family Adenoviridae, presently Simian mastadenovirus A is the single species approved officially for monkey adenoviruses (AdVs), whilst the establishment of six further species (Simian mastadenovirus B to Simian mastadenovirus G) has been proposed in the last few years. We examined the genetic content and phylogenetic relationships of four Old World monkey (OWM) AdV types [namely simian AdV (SAdV)-8, -11, -16 and -19] for which it had been proposed that they should be classified into different AdV species: SAdV-11 to Human mastadenovirus G, and the other three viruses into three novel species. By full genome sequencing, we identified gene contents characteristic for the genus Mastadenovirus. Among the 36 ORFs, 2 genes of different lengths, predicted to encode the adenoviral cellular attachment protein (the fibre), were found. The E3 regions contained six genes, present in every OWM AdV, but lacked the E3 19K gene, which has seemingly appeared only in the ape (hominid) AdV lineages during evolution. For the first time in SAdVs, two other exons belonging to the gene of the so-called U exon protein were also predicted. Phylogenetic calculations, based on the fibre-1 and the major capsid protein, the hexon, implied that recombination events might have happened between different AdV species. Phylogeny inference, based on the viral DNA-dependent DNA polymerase and the penton base protein, further supported the species classification proposed earlier.

Taxonomy proposal for Old World monkey adenoviruses: characterisation of several non-human, non-ape primate adenovirus lineages.

A species classification regarding Old World monkey adenoviruses is proposed. We determined the nucleotide sequences of PCR-amplified fragments from the genes of the IVa2, DNA-dependent DNA polymerase, penton base, and hexon proteins from every simian adenovirus (SAdV) serotype that originated from Old World monkeys for which the full genome sequence had not yet been published. We confirmed that the majority of Old Word monkey SAdVs belong to two previously established species. Interestingly, one is the most recently established human AdV species, Human mastadenovirus G, which includes a single human virus, HAdV-52, as well as SAdV-1, -2, -7, -11, -12, and -15. The other approved species, Simian mastadenovirus A includes SAdV-3, -4, -6, -9, -10, -14, and -48. Several SAdVs (SAdV-5, -8, -49, -50) together with baboon AdV-1 and rhesus monkey AdV strains A1139, A1163, A1173, A1258, A1285, A1296, A1312, A1327 and A1335 have been proposed to be classified into an additional species, Simian mastadenovirus B. Another proposed species, Simian mastadenovirus C has been described for SAdV-19, baboon AdV-2/4 and -3. Our study revealed the existence of four additional AdV lineages. The corresponding new candidate species are Simian mastadenovirus D (for SAdV-13), Simian mastadenovirus E (for SAdV-16), Simian mastadenovirus F (for SAdV-17 and -18), and Simian mastadenovirus G (for SAdV-20). Several biological and genomic properties, such as the host origin, haemagglutination profile, number of fibre genes, and G+C content of the genome, strongly support this classification. Three SAdV strains originating from the American Type Culture Collection turned out to be mixtures of at least two virus types, either of the same species (SAdV-12 and -15 types from Human mastadenovirus G) or of two different species (SAdV-5 types from Simian mastadenovirus B and Human mastadenovirus G).

Sirtuin 3 drives sex-specific responses to age-related changes in mouse embryonic fibroblasts.

The aging process is a complex phenomenon characterised by a gradual decline in physiological functions and an increased susceptibility to age-related diseases. An important factor in aging is mitochondrial dysfunction, which leads to an accumulation of cellular damage over time. Mitochondrial Sirtuin 3 (Sirt3), an important regulator of energy metabolism, plays a central role in maintaining mitochondrial function. Loss of Sirt3 can lead to reduced energy levels and an impaired ability to repair cellular damage, a hallmark of the aging process. In this study we investigated the impact of Sirt3 loss on mitochondrial function, metabolic responses and cellular aging processes in male and female mouse embryonic fibroblasts (MEF) exposed to etoposide-induced DNA damage, which is commonly associated with cellular dysfunction and senescence. We found that Sirt3 contributes to the sex-specific metabolic response to etoposide treatment. While male MEF exhibited minimal damage suggesting potential prior adaptation to stress due to Sirt3 loss, female MEF lacking Sirt3 experienced higher vulnerability to genotoxic stress, implying a pivotal role of Sirt3 in their resistance to such challenges. These findings offer potential insights into therapeutic strategies targeting Sirt3- and sex-specific signalling pathways in diseases associated with DNA damage that play a critical role in the aging process.

Characterization of monkey adenoviruses with three fiber genes.

Although the occurrence of three fiber genes in monkey adenoviruses had already been described, the relatedness of the "extra" fibers have not yet been discussed. Here we report the genome analysis of two simian adenovirus (SAdV) serotypes from Old World monkeys and the phylogenetic analysis of the multiple fiber genes found in these and related AdVs. One of the newly sequenced serotypes (SAdV-2), isolated from a rhesus macaque (Macaca mulatta), was classified into species Human mastadenovirus G (HAdV-G), while the other serotype (SAdV-17), originating from a grivet (Chlorocebus aethiops), classified to Simian mastadenovirus F (SAdV-F). We identified unique features in the gene content of these SAdVs compared to those typical for other members of the genus Mastadenovirus. Namely, in the E1B region of SAdV-2, the 19K gene was replaced by an ITR repetition and a copy of the E4 ORF1 gene. Among the 37 genes in both SAdVs, three genes of different lengths, predicted to code for the cellular attachment proteins (the fibers), were found. These proteins exhibit high diversity. Yet, phylogenetic calculations of their conserved parts could reveal the probable evolutionary steps leading to the multiple-fibered contemporary HAdV and SAdV species. Seemingly, there existed (a) common ancestor(s) with two fiber genes for the lineages of the AdVs in species SAdV-B, -E, -F and HAdV-F, alongside a double-fibered ancestor for today's SAdV-C and HAdV-G, which later diverged into descendants forming today's species. Additionally, some HAdV-G members picked up a third fiber gene either to the left-hand or to the in-between position from the existing two. A SAdV-F progenitor also obtained a third copy to the middle, as observed in SAdV-17. The existence of three fiber genes in these contemporary AdVs brings novel possibilities for the design of optimised AdV-based vectors with potential multiple target binding abilities.

Para-N-Methylpyridinium Pyrenes: Impact of Positive Charge on ds-DNA/RNA and Protein Recognition, Photo-Induced Bioactivity, and Intracellular Localisation.

The 2- and 2,7- substituted para-N-methylpyridinium pyrene cations show high-affinity intercalation into ds-DNAs, whereas their non-methylated analogues interacted with ds-DNA/RNA only in the protonated form (at pH 5), but not at physiological conditions (pH 7). The fluorescence from non-methylated analogues was strongly dependent on the protonation of the pyridines; consequently, they act as fluorescence ratiometric probes for simultaneous detection of both ds-DNA and BSA at pH 5, relying on the ratio between intensities at 420 nm (BSA specific) and 520 nm (DNA specific), whereby exclusively ds-DNA sensing could be switched-off by adjustment to pH 7. Only methylated, permanently charged pyrenes show photoinduced cleavage of circular DNA, attributed to pyrene-mediated irradiation-induced production of singlet oxygen. Consequently, the moderate toxicity of these cations against human cell lines is strongly increased upon irradiation. Detailed studies revealed increased total ROS production in cells treated by the compounds studied, accompanied by cell swelling and augmentation of cellular complexity. The most photo-active 2-para-N-methylpyridinium pyrene showed significant localization at mitochondria, its photo-bioactivity likely due to mitochondrial DNA damage. Other derivatives were mostly non-selectively distributed between various cytoplasmic organelles, thus being less photoactive.

Combination of sirtuin 3 and hyperoxia diminishes tumorigenic properties of MDA-MB-231 cells.

AIMS: Since the role of the major mitochondrial NAD+-dependent deacetylase, sirtuin 3 (Sirt3), is differential in cancer, opposite to the well-known tumor-suppressing effect of hyperoxia, this study aimed to investigate the role of Sirt3 in triple-negative breast cancer (TNBC) cell line MDA-MB-231 upon hyperoxic (95% O2) conditions. MAIN METHODS: MDA-MB-231 cells were stably transfected with Flag-tagged Sirt-3 or empty plasmid. Western blot and real-time PCR were used to monitor the expression of proteins or genes involved in mitochondrial biogenesis, metabolic regulation and antioxidant defense. Immunocytochemistry and confocal microscopy were used to confirm the cellular localization and abundance of proteins. Flow cytometry was used to analyze mitochondrial mass, potential and ROS production, and MTT test as a measure of metabolic activity. Mitotic index analysis, colony-forming unit assay, DNA damage and Annexin V-FITC analyses were used to assess the differences in the growth and apoptosis rate. KEY FINDINGS: Although Sirt3 seemed to improve mitochondrial properties by increasing mitochondrial mass and potential, metabolic activity (Warburg effect) and antioxidative defense (SOD2, Cat), it also increased mitochondrial ROS, induced DNA damage, timp-1 expression, formation of multinucleated cells and apoptosis, and finally markedly reduced the proliferation of MDA-MB-231 cells. All these effects were even more evident upon the hyperoxic treatment, thus pointing towards combined negative effect of Sirt3 and hyperoxia on MDA-MB-231 cells. SIGNIFICANCE: Both Sirt3 and hyperoxia, alone or in combination, have the potential to negatively affect the malignant properties of the MDA-MB-231 cells and should be further explored as a possible therapy for TNBC.

Role of Sirt3 in Differential Sex-Related Responses to a High-Fat Diet in Mice.

Metabolic homeostasis is differently regulated in males and females. Little is known about the mitochondrial Sirtuin 3 (Sirt3) protein in the context of sex-related differences in the development of metabolic dysregulation. To test our hypothesis that the role of Sirt3 in response to a high-fat diet (HFD) is sex-related, we measured metabolic, antioxidative, and mitochondrial parameters in the liver of Sirt3 wild-type (WT) and knockout (KO) mice of both sexes fed with a standard or HFD for ten weeks. We found that the combined effect of Sirt3 and an HFD was evident in more parameters in males (lipid content, glucose uptake, pparγ, cyp2e1, cyp4a14, Nrf2, MnSOD activity) than in females (protein damage and mitochondrial respiration), pointing towards a higher reliance of males on the effect of Sirt3 against HFD-induced metabolic dysregulation. The male-specific effects of an HFD also include reduced Sirt3 expression in WT and alleviated lipid accumulation and reduced glucose uptake in KO mice. In females, with a generally higher expression of genes involved in lipid homeostasis, either the HFD or Sirt3 depletion compromised mitochondrial respiration and increased protein oxidative damage. This work presents new insights into sex-related differences in the various physiological parameters with respect to nutritive excess and Sirt3.

Full genome sequence analysis of a novel adenovirus from a captive polar bear (Ursus maritimus).

The presence of a novel adenovirus (AdV) was detected by PCR and sequencing, in the internal organs of a captive polar bear that had died in the Budapest zoo. The virus content of the samples proved to be high enough to allow for conventional Sanger sequencing on PCR-amplified genomic fragments. With this approach, the sequence of the entire genome of the putative polar bear adenovirus 1 (PBAdV-1) was obtained. Although the genome was found to be short, consisting of 27,952 base pairs merely, with a relatively balanced G + C content of 46.3 %, its organisation corresponded largely to that of a typical mastadenovirus. Every genus-common gene could be identified except that of protein IX. The short E3 region of the PBAdV-1 consisted of two novel, supposedly type-specific ORFs only, whereas no homologue of any of the E3 genes, usually conserved in mastadenoviruses, such as for example that of the 12.5 K protein, were present. In the E4 region, only the highly conserved gene of the 34 K protein was found besides two novel ORFs showing no homology to any known E4 ORFs. In silico sequence analysis revealed putative splicing donor and acceptor sites in the genes of the E1A, IVa2, DNA-dependent DNA polymerase, pTP, 33 K proteins, and also of U exon protein, all being characteristic for mastadenoviruses. Phylogenetic calculations, based on various proteins, further supported that the newly-detected PBAdV is the representative of a new species within the genus Mastadenovirus, and may represent the evolutionary lineage of adenoviruses that coevolved with carnivorans.

Sirt3 Exerts Its Tumor-Suppressive Role by Increasing p53 and Attenuating Response to Estrogen in MCF-7 Cells.

Estrogen (E2) is a major risk factor for the initiation and progression of malignancy in estrogen receptor (ER) positive breast cancers, whereas sirtuin 3 (Sirt3), a major mitochondrial NAD+-dependent deacetylase, has the inhibitory effect on the tumorigenic properties of ER positive MCF-7 breast cancer cells. Since it is unclear if this effect is mediated through the estrogen receptor alpha (ERα) signaling pathway, in this study, we aimed to determine if the tumor-suppressive function of Sirt3 in MCF-7 cells interferes with their response to E2. Although we found that Sirt3 improves the antioxidative response and mitochondrial fitness of the MCF-7 cells, it also increases DNA damage along with p53, AIF, and ERα expression. Moreover, Sirt3 desensitizes cells to the proliferative effect of E2, affects p53 by disruption of the ERα-p53 interaction, and decreases proliferation, colony formation, and migration of the cells. Our observations indicate that these tumor-suppressive effects of Sirt3 could be reversed by E2 treatment only to a limited extent which is not sufficient to recover the tumorigenic properties of the MCF-7 cells. This study provides new and interesting insights with respect to the functional role of Sirt3 in the E2-dependent breast cancers.

De novo expression of transfected sirtuin 3 enhances susceptibility of human MCF-7 breast cancer cells to hyperoxia treatment.

Sirtuin 3 (Sirt3) has a promising role in cancer tumourigenesis and treatment, but there have been controversies about its role as oncogene or tumour suppressor in different types of cancer. Changes in its expression are associated with the excessive production of reactive oxygen species (ROS), thus contributing to mitochondrial dysfunction and age-related pathologies. Hyperoxic treatment (i.e. generator of ROS) was shown to support some tumourigenic properties, but finally suppresses growth of certain mammary carcinoma cells. Due to strikingly reduced Sirt3 level in many breast cancer cell lines, we aimed to clarify the effect of de novo Sirt3 expression upon hyperoxic treatment in the human MCF-7 breast cancer cells. De novo expression of Sirt3 decreased metabolic activity and cellular growth of MCF-7 cells, reduced expression of proangiogenic and epithelial mesenchymal transition genes, induced metabolic switch from glycolysis to oxidative phosphorylation, and decreased abundance of senescent cells. These effects were enhanced upon hyperoxic treatment: induction of DNA damage and upregulation of p53, with an increase of ROS levels followed by mitochondrial and antioxidant dysfunction, resulted in additional reduction of metabolic activity and inhibition of cellular growth and survival. The mitigation of tumorigenic properties and enhancement of the susceptibility of the MCF-7 breast cancer cells to the hyperoxic treatment upon de novo Sirt3 expression indicates that these factors, individually and in combination, should be further explored in vitro and particularly in vivo, as an adjuvant tumour therapy in breast cancer malignancies.

Circumventing antivector immunity: potential use of nonhuman adenoviral vectors.

Adenoviruses are efficient gene delivery vectors based on their ability to transduce a wide variety of cell types and drive high-level transient transgene expression. While there have been advances in modifying human adenoviral (HAdV) vectors to increase their safety profile, there are still pitfalls that need to be further addressed. Preexisting humoral and cellular immunity against common HAdV serotypes limits the efficacy of gene transfer and duration of transgene expression. As an alternative, nonhuman AdV (NHAdV) vectors can circumvent neutralizing antibodies against HAdVs in immunized mice and monkeys and in human sera, suggesting that NHAdV vectors could circumvent preexisting humoral immunity against HAdVs in a clinical setting. Consequently, there has been an increased interest in developing NHAdV vectors for gene delivery in humans. In this review, we outline the recent advances and limitations of HAdV vectors for gene therapy and describe examples of NHAdV vectors focusing on their immunogenicity, tropism, and potential as effective gene therapy vehicles.