Abstract P347: Transcriptional Features Of Biological Age Maintained In Cultured Cardiac Interstitial Cells

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Oscar E Echeagaray ◽  
Taeyong Kim ◽  
Alex Casillas ◽  
Megan M Monsanto ◽  
Mark A Sussman

Introduction: Ex vivo expansion of cells is necessary in regenerative medicine to generate large populations for therapeutic use. Adaptation to culture conditions prompt an increase in transcriptome diversity and decreased population heterogeneity in cKit+ cardiac interstitial cells (cCICs). The “transcriptional memory” influenced by cellular origin remains unexplored and is likely to differ between neonatal versus senescent input cells undergoing culture expansion. Approach: cCICs isolated from neonatal and adult cardiac tissue (Left Ventricular Assist Device; LVAD). Single cell libraries from in vitro expanded cells were prepared following five passages as previously demonstrated by our group to promote transcriptional homogeneity. “Transcriptional memory” was surveyed via bioinformatic analysis including unsupervised clustering, differential expression analysis, gene ontology and pathway analysis. Transitional states were assessed through pseudotime analysis. Results: Cell cycle imprint associated with biological age after culture was observed in Neonatal cCICs via upregulation of G2M genes. LVAD derived cCICs retained a widespread senescent profile, in particular high expression of interleukins and elements of the senescence associated secretory phenotype (SASP). Nuclear pore complex TPR and UBC9 and translation initiation factors, displayed age-associated downregulation of elements in the RNA transport and processing pathway. Pathway and co-expression analysis of fibroblast markers Ddr2, Tcf21, Vimentin, Periostin and Collagen deposition markers indicated a primed fibrotic phenotype in senescent cells. A small subset of cCICs exist in a transcriptional continuum between “youthful” phenotype and the damaged microenvironment of adult tissue in which they were embedded. Conclusion: The influence of age, pathology and the cellular stress associated to the in vivo tissue microenvironment persist after culture adaptation, influencing targets of 1) cell cycle, 2) senescence associated secretory phenotype (SASP), 3) RNA transport, and 4) ECM-receptor/fibrosis. The connate transcriptional phenotypes offer fundamental biological insight and highlights cellular input as a consideration in culture expansion and adoptive transfer protocols.

2018 ◽  
Author(s):  
Charlene Boumendilrid ◽  
Priya Hari ◽  
Karl C. F. Olsen ◽  
Juan Carlos Acosta ◽  
Wendy A. Bickmore

AbstractOncogene induced senescence (OIS) is a cell cycle arrest program triggered by oncogenic signalling. An important characteristic of OIS is activation of the senescence associated secretory phenotype (SASP)1 which can reinforce cell cycle arrest, lead to paracrine senescence but also promote tumour progression2–4. Concomitant with cell cycle arrest and the SASP activation, OIS cells undergo a striking nuclear chromatin reorganization, with loss of heterochromatin from the nuclear periphery and the appearance of internal senescence-associated heterochromatin foci (SAHF)5. The mechanisms by which SAHF are formed, and their role in cell cycle arrest and expression of the SASP, remain poorly understood. Here we show that nuclear pore density increases during OIS and is responsible for SAHF formation. In particular, we show that the nucleoporin TPR is required for both SAHF formation and maintenance. The TPR-induced loss of SAHF does not affect cell cycle arrest but completely abrogates the SASP. Our results uncover a previously unknown role of nuclear pores in heterochromatin reorganization in mammalian nuclei and in senescence, which uncouples the cell cycle arrest from the SASP.


2020 ◽  
Vol 90 ◽  
pp. 125-134 ◽  
Author(s):  
Veronica Porterfield ◽  
Shahzad S. Khan ◽  
Erin P. Foff ◽  
Mehmet Murat Koseoglu ◽  
Isabella K. Blanco ◽  
...  

2019 ◽  
Vol 20 (6) ◽  
pp. 1486 ◽  
Author(s):  
Miguel Carracedo ◽  
Oscar Persson ◽  
Peter Saliba-Gustafsson ◽  
Gonzalo Artiach ◽  
Ewa Ehrenborg ◽  
...  

Autophagy serves as a cell survival mechanism which becomes dysregulated under pathological conditions and aging. Aortic valve thickening and calcification causing left ventricular outflow obstruction is known as calcific aortic valve stenosis (CAVS). CAVS is a chronic and progressive disease which increases in incidence and severity with age. Currently, no medical treatment exists for CAVS, and the role of autophagy in the disease remains largely unexplored. To further understand the role of autophagy in the progression of CAVS, we analyzed expression of key autophagy genes in healthy, thickened, and calcified valve tissue from 55 patients, and compared them with nine patients without significant CAVS, undergoing surgery for aortic regurgitation (AR). This revealed a upregulation in autophagy exclusively in the calcified tissue of CAVS patients. This difference in autophagy between CAVS and AR was explored by LC3 lipidation in valvular interstitial cells (VICs), revealing an upregulation in autophagic flux in CAVS patients. Inhibition of autophagy by bafilomycin-A1 led to a decrease in VIC survival. Finally, treatment of VICs with high phosphate led to an increase in autophagic activity. In conclusion, our data suggests that autophagy is upregulated in the calcified tissue of CAVS, serving as a compensatory and pro-survival mechanism.


2018 ◽  
Author(s):  
Priya Hari ◽  
Fraser R. Millar ◽  
Nuria Tarrats ◽  
Jodie Birch ◽  
Curtis J. Rink ◽  
...  

ABSTRACTCellular senescence is a stress response program characterised by a robust cell cycle arrest and the induction of a pro-inflammatory senescence-associated secretory phenotype (SASP) that is triggered through an unknown mechanism. Here, we show that during oncogene-induced senescence (OIS), the Toll-like receptor TLR2 and its partner TLR10 are key mediators of senescence in vitro and in murine models. TLR2 promotes cell cycle arrest by regulating the tumour suppressors p53-p21CIP1, p16INK4a and p15INK4b, and regulates the SASP through the induction of the acute-phase serum amyloids A1 and A2 (A-SAA) that, in turn, function as the damage associated molecular patterns (DAMPs) signalling through TLR2 in OIS. Finally, we found evidence that the cGAS-STING cytosolic DNA sensing pathway primes TLR2 and A-SAA expression in OIS. In summary, we report that innate immune sensing of senescence-associated DAMPs by TLR2 controls the SASP and reinforces the cell cycle arrest program in OIS.


1997 ◽  
Vol 138 (1) ◽  
pp. 65-80 ◽  
Author(s):  
Dirk Görlich ◽  
Marylena Dabrowski ◽  
F. Ralf Bischoff ◽  
Ulrike Kutay ◽  
Peer Bork ◽  
...  

The importin-α/β complex and the GTPase Ran mediate nuclear import of proteins with a classical nuclear localization signal. Although Ran has been implicated also in a variety of other processes, such as cell cycle progression, a direct function of Ran has so far only been demonstrated for importin-mediated nuclear import. We have now identified an entire class of ∼20 potential Ran targets that share a sequence motif related to the Ran-binding site of importin-β. We have confirmed specific RanGTP binding for some of them, namely for two novel factors, RanBP7 and RanBP8, for CAS, Pse1p, and Msn5p, and for the cell cycle regulator Cse1p from Saccharomyces cerevisiae. We have studied RanBP7 in more detail. Similar to importin-β, it prevents the activation of Ran's GTPase by RanGAP1 and inhibits nucleotide exchange on RanGTP. RanBP7 binds directly to nuclear pore complexes where it competes for binding sites with importin-β, transportin, and apparently also with the mediators of mRNA and U snRNA export. Furthermore, we provide evidence for a Ran-dependent transport cycle of RanBP7 and demonstrate that RanBP7 can cross the nuclear envelope rapidly and in both directions. On the basis of these results, we propose that RanBP7 might represent a nuclear transport factor that carries an as yet unknown cargo, which could apply as well for this entire class of related RanGTP-binding proteins.


2021 ◽  
pp. 1-26
Author(s):  
Sze Chung Yuen ◽  
Simon Ming-Yuen Lee ◽  
Siu-wai Leung

Background: Neuronal cell cycle re-entry (CCR) is a mechanism, along with amyloid-β (Aβ) oligomers and hyperphosphorylated tau proteins, contributing to toxicity in Alzheimer’s disease (AD). Objective: This study aimed to examine the putative factors in CCR based on evidence corroboration by combining meta-analysis and co-expression analysis of omic data. Methods: The differentially expressed genes (DEGs) and CCR-related modules were obtained through the differential analysis and co-expression of transcriptomic data, respectively. Differentially expressed microRNAs (DEmiRNAs) were extracted from the differential miRNA expression studies. The dysregulations of DEGs and DEmiRNAs as binary outcomes were independently analyzed by meta-analysis based on a random-effects model. The CCR-related modules were mapped to human protein-protein interaction databases to construct a network. The importance score of each node within the network was determined by the PageRank algorithm, and nodes that fit the pre-defined criteria were treated as putative CCR-related factors. Results: The meta-analysis identified 18,261 DEGs and 36 DEmiRNAs, including genes in the ubiquitination proteasome system, mitochondrial homeostasis, and CCR, and miRNAs associated with AD pathologies. The co-expression analysis identified 156 CCR-related modules to construct a protein-protein interaction network. Five genes, UBC, ESR1, EGFR, CUL3, and KRAS, were selected as putative CCR-related factors. Their functions suggested that the combined effects of cellular dyshomeostasis and receptors mediating Aβ toxicity from impaired ubiquitination proteasome system are involved in CCR. Conclusion: This study identified five genes as putative factors and revealed the significance of cellular dyshomeostasis in the CCR of AD.


Development ◽  
2019 ◽  
Vol 146 (12) ◽  
pp. dev173476 ◽  
Author(s):  
Guang Li ◽  
Lei Tian ◽  
William Goodyer ◽  
Eric J. Kort ◽  
Jan W. Buikema ◽  
...  

Author(s):  
Leigh A Bradley ◽  
Alexander Young ◽  
Hongbin Li ◽  
Helen O Billcheck ◽  
Matthew J Wolf

Rationale: Endogenously cycling adult cardiomyocytes (CMs) increase after myocardial infarction (MI) but remain scare, and are generally thought not to contribute to myocardial function. However, this broadly held assumption has not been tested, mainly because of the lack of transgenic reporters that restrict Cre expression to adult CMs that reenter the cell cycle. Objective: We created and validated a new transgenic mouse, αMHC-MerDreMer-Ki67p-RoxedCre::Rox-Lox-tdTomato-eGFP (denoted αDKRC) that restricts Cre expression to cycling adult CMs and uniquely integrates spatial and temporal adult CM cycling events based on the DNA specificities of orthologous Dre- and Cre recombinases. We then created mice that expressed an inducible Diphtheria toxin (DTA), αDKRC::DTA mice, in adult cycling CMs and examined the effects of ablating these endogenously cycling CMs on myocardial function after Ischemic-Reperfusion (I/R) MI. Methods and Results: A tandem αDKRC transgene was designed, validated in cultured cells, and used to make transgenic mice. The αDKRC transgene integrated between MYH6 and MYH7 and did not disrupt expression of the surrounding genes. Compared to controls, αDKRC::RLTG mice treated with Tamoxifen expressed tdTomato+ in CMs with rare Bromodeoxyuridine (BrdU)+, eGFP+ CMs, consistent with reentry of the cell cycle. We then pre-treated αDKRC::RLTG mice with Tamoxifen to activate the reporter before sham or reperfusion (I/R) myocardial infarction (MI) surgeries. Compared to Sham surgery, the I/R MI group had increased single and paired eGFP+ CMs predominantly in the border zones (5.8 {plus minus} 0.5 vs. 3.3 {plus minus} 0.3 CMs per ten-micron section, N = 8-9 mice per group, n = 16-24 sections per mouse), indicative of cycled CMs. The single to paired eGFP+ CM ratio was ~9 to 1 (5.2 {plus minus} 0.4 single vs. 0.6 {plus minus} 0.2 paired CMs) in the I/R MI group after MI, suggesting that cycling CMs were more likely to undergo polyploidy than replication. The ablation of endogenously cycling adult CMs in αDKRC::DTA mice caused progressive worsening left ventricular chamber size and function after I/R MI, compared to controls. Conclusions: Although scarce, endogenously cycling adult CMs contribute to myocardial function after injury, suggesting that these cells may be physiologically relevant.


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