Project description:To investigate the mechanisms of PI3Kα-induced senescence, we performed a gene expression microarray analysis with MCF-10A/H and parental MCF-10A cells.
Project description:We set out to characterize the transcriptional heterogeneity of the senescence program using a large number of whole-transcriptome sequencing datasets generated by us or publicly available. We identify a number of senescence transcriptional signatures associated to specific stresses or cell types. We also merge all the studies to identify and validate the genes that are universally differentially regulated during senescence.
Project description:Cells are subjected to dynamic mechanical environments which impart various forces and induce cellular responses. In age-related conditions like pulmonary fibrosis, there is both an increase in tissue stiffness and an accumulation of senescent cells, leading to elevated tension in fibroblasts among other cells. While senescent cells produce a senescence-associated secretory phenotype (SASP), the impact of physical stimuli on both cellular senescence and SASP is not well understood. Here, we show that mechanical tension, modeled using cell culture substrate rigidity, influences senescent cell markers like SA-beta-gal and secretory phenotypes. Comparing human primary pulmonary fibroblasts (IMR-90) cultured on physiological (2 kPa), fibrotic (50 kPa), and plastic (3 GPa) substrates followed by senescence induction using doxorubicin, we identified unique high-stiffness-driven secretory protein profiles using mass spectrometry and transcriptomic signatures, both showing an enrichment in collagen proteins. Computational meta-analysis of human interstitial lung disease single-cell RNA sequencing datasets confirmed these genes are highly expressed in disease samples and strongly correlate with mechanotransduction and senescence-related pathways. Thus, mechanical forces shape cell senescence and their secretory phenotypes.
Project description:Cellular senescence is described as an irreversible cell cycle arrest induced in response to various stresses. Senescent cells are characterised by heterogeneous signalling alterations, complex secretory phenotype, known as senescence-associated secretory phenotype (SASP), and diverse transcriptomic profile. With the aim to investigate senescence heterogeneity and identify conserved transctiptomic alterations and universal senescence markers, we performed RNA-seq and multiplex proteomic analysis in proteasome inhibition-induced and stress-induced premature senescence models of HFL1 and BJ human fibroblasts. Our data revealed diverse transcriptomic signatures, but also, 231 common differentially expressed genes related to cell division and ECM remodelling, and enriched pathways that remained conserved among the different models with senescence onset. Moreover, we identified a subset of proteins and validated them in replicative senescent models. These proteins are involved in cell cycle arrest and promote a pro-inflammatory environment in premature and replicative senescence models. We suggest that the simultaneous analysis of p21, p-c-JUN, BCL-xL and survivin in cellular lysates, and IL-8, GM-CSF, GDF-15 and GROa in culture supernatants can provide a powerful tool for the identification and monitoring of senescent cells and can support the assessment of the efficacy of potential senotherapeutic approaches.
Project description:Noncoding RNAs include small transcripts, such as microRNAs and piwi-interacting RNAs, and a wide range of long noncoding RNAs (lncRNAs). Although many lncRNAs have been identified, only a small number of lncRNAs have been characterized functionally. Here, we sought to identify lncRNAs differentially expressed during replicative senescence. We compared lncRNAs expressed in proliferating, early-passage, 'young' human diploid WI-38 fibroblasts [population doubling (PDL) 20] with those expressed in senescent, late-passage, 'old' fibroblasts (PDL 52) by RNA sequencing (RNA-Seq). Numerous transcripts in all lncRNA groups (antisense lncRNAs, pseudogene-encoded lncRNAs, previously described lncRNAs and novel lncRNAs) were validated using reverse transcription (RT) and real-time, quantitative (q)PCR. Among the novel senescence-associated lncRNAs (SAL-RNAs) showing lower abundance in senescent cells, SAL-RNA1 (XLOC_023166) was found to delay senescence, because reducing SAL-RNA1 levels enhanced the appearance of phenotypic traits of senescence, including an enlarged morphology, positive β-galactosidase activity, and heightened p53 levels. Our results reveal that the expression of known and novel lncRNAs changes with senescence and suggests that SAL-RNAs play direct regulatory roles in this important cellular process. RNA was extracted from both young and senescent WI-38 cells and used for total RNA-Seq.