Self-Renewal Signalling in Presenescent Tetraploid IMR90 Cells

Endopolyploidy and genomic instability are shared features of both stress-induced cellular senescence and malignant growth. Here, we examined these facets in the widely used normal human fibroblast model of senescence, IMR90. At the presenescence stage, a small (2–7%) proportion of cells overcome the 4n-G1 checkpoint, simultaneously inducing self-renewal (NANOG-positivity), the DNA damage response (DDR; γ-H2AX-positive foci), and senescence (p16inka4a- and p21CIP1-positivity) signalling, some cells reach octoploid DNA content and divide. All of these markers initially appear and partially colocalise in the perinucleolar compartment. Further, with development of senescence and accumulation of p16inka4a and p21CIP1, NANOG is downregulated in most cells. The cells increasingly arrest in the 4n-G1 fraction, completely halt divisions and ultimately degenerate. A positive link between DDR, self-renewal, and senescence signalling is initiated in the cells overcoming the tetraploidy barrier, indicating that cellular and molecular context of induced tetraploidy during this period of presenescence is favourable for carcinogenesis

Monogenic Versus Multifactorial Inheritance in the Development of Isolated Cleft Palate : A Whole Genome Sequencing Study

Funding Information: This project was funded by the Latvian Research Council, Grant no: lzp-2020/2-0374 “Deciphering the genetic mechanisms of the individuals with isolated cleft palate by whole genome sequencing”. SP was supported by an Estonian Research Council grant (MOBTP175). Publisher Copyright: Copyright © 2022 Lace, Pajusalu, Livcane, Grinfelde, Akota, Mauliņa, Barkāne, Stavusis and Inashkina.Craniofacial morphogenesis is highly complex, as is the anatomical region involved. Errors during this process, resulting in orofacial clefts, occur in more than 400 genetic syndromes. Some cases of cleft lip and/or palate (CLP) are caused by mutations in single genes; however, complex interactions between genetic and environmental factors are considered to be responsible for the majority of non-syndromic CLP development. The aim of the current study was to identify genetic risk factors in patients with isolated cleft palate (CP) by whole genome sequencing. Patients with isolated CP (n = 30) recruited from the Riga Cleft Lip and Palate Centre, Institute of Stomatology, Riga, were analyzed by whole genome sequencing. Pathogenic or likely pathogenic variants were discovered in genes associated with CP (TBX22, COL2A1, FBN1, PCGF2, and KMT2D) in five patients; hence, rare disease variants were identified in 17% of patients with non-syndromic isolated CP. Our results were relevant to routine genetic counselling practice and genetic testing recommendations. Based on our data, we propose that all newborns with orofacial clefts should be offered genetic testing, at least for a panel of known CLP genes. Only if the results are negative and there is no suggestive family history or additional clinical symptoms (which would support additional exome or genome-wide investigation), should multifactorial empiric recurrence risk prediction tools be applied for families.publishersversionPeer reviewe

The Price of Human Evolution : Cancer-Testis Antigens, the Decline in Male Fertility and the Increase in Cancer

Publisher Copyright: © 2023 by the authors.The increasing frequency of general and particularly male cancer coupled with the reduction in male fertility seen worldwide motivated us to seek a potential evolutionary link between these two phenomena, concerning the reproductive transcriptional modules observed in cancer and the expression of cancer-testis antigens (CTA). The phylostratigraphy analysis of the human genome allowed us to link the early evolutionary origin of cancer via the reproductive life cycles of the unicellulars and early multicellulars, potentially driving soma-germ transition, female meiosis, and the parthenogenesis of polyploid giant cancer cells (PGCCs), with the expansion of the CTA multi-families, very late during their evolution. CTA adaptation was aided by retrovirus domestication in the unstable genomes of mammals, for protecting male fertility in stress conditions, particularly that of humans, as compensation for the energy consumption of a large complex brain which also exploited retrotransposition. We found that the early and late evolutionary branches of human cancer are united by the immunity-proto-placental network, which evolved in the Cambrian and shares stress regulators with the finely-tuned sex determination system. We further propose that social stress and endocrine disruption caused by environmental pollution with organic materials, which alter sex determination in male foetuses and further spermatogenesis in adults, bias the development of PGCC-parthenogenetic cancer by default.Peer reviewe

Role of stress-activated OCT4A in the cell fate decisions of embryonal carcinoma cells treated with etoposide

Tumor cellular senescence induced by genotoxic treatments has recently been found to be paradoxically linked to the induction of “stemness.” This observation is critical as it directly impinges upon the response of tumors to current chemo-radio-therapy treatment regimens. Previously, we showed that following etoposide (ETO) treatment embryonal carcinoma PA-1 cells undergo a p53-dependent upregulation of OCT4A and p21Cip1 (governing self-renewal and regulating cell cycle inhibition and senescence, respectively). Here we report further detail on the relationship between these and other critical cell-fate regulators. PA-1 cells treated with ETO display highly heterogeneous increases in OCT4A and p21Cip1 indicative of dis-adaptation catastrophe. Silencing OCT4A suppresses p21Cip1, changes cell cycle regulation and subsequently suppresses terminal senescence; p21Cip1-silencing did not affect OCT4A expression or cellular phenotype. SOX2 and NANOG expression did not change following ETO treatment suggesting a dissociation of OCT4A from its pluripotency function. Instead, ETO-induced OCT4A was concomitant with activation of AMPK, a key component of metabolic stress and autophagy regulation. p16ink4a, the inducer of terminal senescence, underwent autophagic sequestration in the cytoplasm of ETO-treated cells, allowing alternative cell fates. Accordingly, failure of autophagy was accompanied by an accumulation of p16ink4a, nuclear disintegration, and loss of cell recovery. Together, these findings imply that OCT4A induction following DNA damage in PA-1 cells, performs a cell stress, rather than self-renewal, function by moderating the expression of p21Cip1, which alongside AMPK helps to then regulate autophagy. Moreover, this data indicates that exhaustion of autophagy, through persistent DNA damage, is the cause of terminal cellular senescence

Overview of Neuromuscular Disorder Molecular Diagnostic Experience for the Population of Latvia

Funding Information: The Article Processing Charge was funded by the authors. Publisher Copyright: © American Academy of Neurology.Background and ObjectivesGenetic testing has become an integral part of health care, allowing the confirmation of thousands of hereditary diseases, including neuromuscular disorders (NMDs). The reported average prevalence of individual inherited NMDs is 3.7-4.99 per 10,000. This number varies greatly in the selected populations after applying population-wide studies. The aim of this study was to evaluate the effect of genetic analysis as the first-tier test in patients with NMD and to calculate the disease prevalence and allelic frequencies for reoccurring genetic variants.MethodsPatients with NMD from Latvia with molecular tests confirming their diagnosis in 2008-2020 were included in this retrospective study.ResultsDiagnosis was confirmed in 153 unique cases of all persons tested. Next-generation sequencing resulted in a detection rate of 37%. Two of the most common childhood-onset NMDs in our population were spinal muscular atrophy and dystrophinopathies, with a birth prevalence of 1.01 per 10,000 newborns and 2.08 per 10,000 (male newborn population), respectively. The calculated point prevalence was 0.079 per 10,000 for facioscapulohumeral muscular dystrophy type 1, 0.078 per 10,000 for limb-girdle muscular dystrophy, 0.073 per 10,000 for nondystrophic congenital myotonia, 0.052 per 10,000 for spinobulbar muscular atrophy, and 0.047 per 10,000 for type 1 myotonic dystrophy.DiscussionDNA diagnostics is a successful approach. The carrier frequencies of the common CAPN3, FKRP, SPG11, and HINT1 gene variants as well as that of the SMN1 gene exon 7 deletion in the population of Latvia are comparable with data from Europe. The carrier frequency of the CLCN1 gene variant c.2680C>T p.(Arg894Ter) is 2.11%, and consequently, congenital myotonia is the most frequent NMD in our population.publishersversionPeer reviewe

Food quality affects the expression of antimicrobial peptide genes upon simulated parasite attack in the larvae of greater wax moth

Predator-prey interactions are an important evolutionary force affecting the immunity of the prey. Parasitoids and mites pierce the cuticle of their prey, which respond by activating their immune system against predatory attacks. Immunity is a costly function for the organism, as it often competes with other life-history traits for limited nutrients. We tested whether the expression of antimicrobial peptides (AMP) of the larvae of the greater wax moth Galleria mellonella (L.) (Lepidoptera: Pyralidae) changes as a consequence of insertion of a nylon monofilament, which acts like a synthetic parasite. The treatment was done for larvae grown on a high-quality vs. a low-quality diet. The expression of Gloverin and 6-tox were upregulated in response to the insertion of the nylon monofilament. The expression of 6-tox, Cecropin-D, and Gallerimycin were significantly higher in the low-quality diet' group than in the high-quality diet' group. As food quality seems to affect AMP gene expression in G. mellonella larvae, it should always be controlled for in studies on bacterial and fungal infections in G. mellonella

Survival at the brink: Chromatin autophagy of tumor cells in response to genotoxic challenge

Survival of tumor cells after genotoxic damage, in particular those lacking TP53, requires a sophisticated series of cellular processes and ultrastructural reorganizations. Together these operations help to overcome the paradox between cellular senescence, high levels of DNA damage and the renewal of stemness.Recently we reported that autophagic chromatin elimination is a key component of the survival response. In this chapter, we detail the many ways in which chromatin autophagy can occur in tumor cells, discuss its evolutionary precursors, and reveal how it may help to determine cell fate

DNA methylation of the Oct4A enhancers in embryonal carcinoma cells after etoposide treatment is associated with alternative splicing and altered pluripotency in reversibly senescent cells

Funding Information: Dr. Bogdanova-Jatniece is acknowledged for sharing the sequences for Sox2 RT-qPCR. The authors thank Prof. MS Cragg for reading the manuscript. The study was supported by the Europe Social Fund Project, project No. 2013/0023/1DP/1.1.1.2.0/13/APIA/VIAA/037. The publishing costs are covered by the Riga Stradins University. Funding Information: The study was supported by the Europe Social Fund Project, project No. 2013/0023/1DP/1.1.1.2.0/13/APIA/VIAA/037. The publishing costs are covered by the Riga Stradins University. Publisher Copyright: © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Copyright: Copyright 2018 Elsevier B.V., All rights reserved.The epigenetic mechanisms underlying chemoresistance in cancer cells resulting from drug-induced reversible senescence are poorly understood. Chemoresistant ESC-like embryonal carcinoma PA1 cells treated with etoposide (ETO) were previously found to undergo prolonged G2 arrest with transient p53-dependent upregulation of opposing fate regulators, p21CIP1 (senescence) and OCT4A (self-renewal). Here we report on the analysis of the DNA methylation state of the distal enhancer (DE) and proximal enhancer (PE) of the Oct4A gene during this dual response. When compared to non–treated controls the methylation level increased from 1.3% to 12.5% and from 3% to 19.4%, in the DE and PE respectively. It included CpG and non-CpG methylation, which was not chaotic but presented two patterns in each enhancer. Discorrelating with methylation of enhancers, the transcription of Oct4A increased, however, a strong expression of the splicing form Oct4B was also induced, along with down-regulation of the Oct4A partners of in the pluripotency/self-renewal network Sox2 and Lin28. WB demonstrated disjoining of the OCT4A protein from the chromatin-bound fraction. In survival clones, methylation of the DE was considerably erased, while some remnant of methylation of the PE was still observed. The alternative splicing for Oct4B was reduced, Oct4A level insignificantly decreased, while the expression of Sox2 and Lin28 recovered, all three became proportionally above the control. These findings indicate the involvement of the transient patterned methylation of the Oct4A enhancers and alternative splicing in the adaptive regulation of cell fate choice during the p53-dependant dual state of reversible senescence in ESC-like cancer stem cells.publishersversionPeer reviewe

The Role of mitotic slippage in creating a “female pregnancy-like system” in a single polyploid giant cancer cell

In our recent work, we observed that triple-negative breast cancer MDA-MB-231 cells respond to doxorubicin (DOX) via “mitotic slippage” (MS), discarding cytosolic damaged DNA during the process that provides their resistance to this genotoxic treatment. We also noted two populations of polyploid giant cells: those budding surviving offspring, versus those reaching huge ploidy by repeated MS and persisting for several weeks. Their separate roles in the recovery from treatment remained unclear. The current study was devoted to characterising the origin and relationship of these two sub-populations in the context of MS. MS was hallmarked by the emergence of nuclear YAP1/OCT4A/MOS/EMI2-positivity featuring a soma-germ transition to the meiotic-metaphase-arrested “maternal germ cell”. In silico, the link between modules identified in the inflammatory innate immune response to cytosolic DNA and the reproductive module of female pregnancy (upregulating placenta developmental genes) was observed in polyploid giant cells. Asymmetry of the two subnuclei types, one repairing DNA and releasing buds enriched by CDC42/ACTIN/TUBULIN and the other persisting and degrading DNA in a polyploid giant cell, was revealed. We propose that when arrested in MS, a “maternal cancer germ cell” may be parthenogenetically stimulated by the placental proto-oncogene parathyroid-hormone-like-hormone, increasing calcium, thus creating a ”female pregnancy-like” system within a single polyploid giant cancer cell.<br/

Dupuytren's Contracture Cosegregation with Limb-Girdle Muscle Dystrophy

Limb-girdle muscular dystrophies (LGMDs) is a heterogeneous group of muscular dystrophies that mostly affect the pelvic and shoulder girdle muscle groups. We report here a case of neuromuscular disease associated with Dupuytren's contracture, which has never been described before as cosegregating with an autosomal dominant type of inheritance. Dupuytren's contracture is a common disease, especially in Northern Europe. Comorbid conditions associated with Dupuytren's contracture are repetitive trauma to the hands, diabetes, and seizures, but it has never before been associated with neuromuscular disease. We hypothesize that patients may harbor mutations in genes with functions related to neuromuscular disease and Dupuytren's contracture development