scholarly journals Proteostasis collapse, a hallmark of aging, hinders the chaperone-Start network and arrests cells in G1

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
David F Moreno ◽  
Kirsten Jenkins ◽  
Sandrine Morlot ◽  
Gilles Charvin ◽  
Attila Csikasz-Nagy ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Cellular Senescence ◽  
Cell Senescence ◽  
Chaperone Activity ◽  
Yeast Cells ◽  
G1 Arrest ◽  
Dependent Manner ◽  
Severe Reduction ◽  
G1 Cyclin ◽  
Nuclear Levels

Loss of proteostasis and cellular senescence are key hallmarks of aging, but direct cause-effect relationships are not well understood. We show that most yeast cells arrest in G1 before death with low nuclear levels of Cln3, a key G1 cyclin extremely sensitive to chaperone status. Chaperone availability is seriously compromised in aged cells, and the G1 arrest coincides with massive aggregation of a metastable chaperone-activity reporter. Moreover, G1-cyclin overexpression increases lifespan in a chaperone-dependent manner. As a key prediction of a model integrating autocatalytic protein aggregation and a minimal Start network, enforced protein aggregation causes a severe reduction in lifespan, an effect that is greatly alleviated by increased expression of specific chaperones or cyclin Cln3. Overall, our data show that proteostasis breakdown, by compromising chaperone activity and G1-cyclin function, causes an irreversible arrest in G1, configuring a molecular pathway postulating proteostasis decay as a key contributing effector of cell senescence.

scholarly journals Proteostasis collapse halts G1 progression and delimits replicative lifespan

2019 ◽  
Author(s):  
David F. Moreno ◽  
Kirsten Jenkins ◽  
Sandrine Morlot ◽  
Gilles Charvin ◽  
Attila Csikász-Nagy ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Protein Aggregation ◽  
Cellular Senescence ◽  
Yeast Cells ◽  
Cell Aging ◽  
G1 Arrest ◽  
Dependent Manner ◽  
Replicative Lifespan ◽  
Nuclear Levels

AbstractLoss of proteostasis and cellular senescence are key hallmarks of cell aging, but whether they are subject to direct cause-effect relationships is not known. We show that most yeast cells arrest in G1 before death with low nuclear levels of cyclin Cln3, a key activator of Start extremely sensitive to chaperone status. Chaperone availability is seriously compromised in aged cells, and the G1 arrest coincides with massive aggregation of a metastable chaperone-activity reporter. A mathematical model integrating autocatalytic protein aggregation and a minimal Start network recapitulates empirical observations. As key predictions, G1-cyclin overexpression increases lifespan in a chaperone-dependent manner, and lifespan reduction by enforced protein aggregation is greatly alleviated by increased expression of specific chaperones or cyclin Cln3. Overall, our data indicate the crucial role of chaperone malfunction in setting lifespan in yeast cells, and configure a molecular pathway whereby proteostasis breakdown acts as a direct effector of cell senescence.

Screening for small molecule modulators of Hsp70 chaperone activity using protein aggregation suppression assays: inhibition of the plasmodial chaperone PfHsp70-1

2011 ◽  
Vol 392 (5) ◽  
Author(s):  
Ingrid L. Cockburn ◽  
Eva-Rachele Pesce ◽  
Jude M. Pryzborski ◽  
Michael T. Davies-Coleman ◽  
Peter G.K. Clark ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Small Molecule ◽  
Drug Target ◽  
Molecular Probes ◽  
Chaperone Activity ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Chaperone Function ◽  
Hsp70 Chaperone ◽  
Small Molecule Modulators

Abstract Plasmodium falciparum heat shock protein 70 (PfHsp70-1) is thought to play an essential role in parasite survival and virulence in the human host, making it a potential antimalarial drug target. A malate dehydrogenase based aggregation suppression assay was adapted for the screening of small molecule modulators of Hsp70. A number of small molecules of natural (marine prenylated alkaloids and terrestrial plant naphthoquinones) and related synthetic origin were screened for their effects on the protein aggregation suppression activity of purified recombinant PfHsp70-1. Five compounds (malonganenone A-C, lapachol and bromo-β-lapachona) were found to inhibit the chaperone activity of PfHsp70-1 in a concentration dependent manner, with lapachol preferentially inhibiting PfHsp70-1 compared to another control Hsp70. Using growth inhibition assays on P. falciparum infected erythrocytes, all of the compounds, except for malonganenone B, were found to inhibit parasite growth with IC50 values in the low micromolar range. Overall, this study has identified two novel classes of small molecule inhibitors of PfHsp70-1, one representing a new class of antiplasmodial compounds (malonganenones). In addition to demonstrating the validity of PfHsp70-1 as a possible drug target, the compounds reported in this study will be potentially useful as molecular probes for fundamental studies on Hsp70 chaperone function.

scholarly journals Mechanisms of Androgen Receptor Agonist- and Antagonist-Mediated Cellular Senescence in Prostate Cancer

Cancers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1833 ◽  
Author(s):  
Miriam Kokal ◽  
Kimia Mirzakhani ◽  
Thanakorn Pungsrinont ◽  
Aria Baniahmad
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Cellular Senescence ◽  
Cellular Response ◽  
Cell Cycle Progression ◽  
Current Knowledge ◽  
Ex Vivo ◽  
Cell Senescence ◽  
Dependent Manner ◽  
Androgen Levels

The androgen receptor (AR) plays a leading role in the control of prostate cancer (PCa) growth. Interestingly, structurally different AR antagonists with distinct mechanisms of antagonism induce cell senescence, a mechanism that inhibits cell cycle progression, and thus seems to be a key cellular response for the treatment of PCa. Surprisingly, while physiological levels of androgens promote growth, supraphysiological androgen levels (SAL) inhibit PCa growth in an AR-dependent manner by inducing cell senescence in cancer cells. Thus, oppositional acting ligands, AR antagonists, and agonists are able to induce cellular senescence in PCa cells, as shown in cell culture model as well as ex vivo in patient tumor samples. This suggests a dual AR-signaling dependent on androgen levels that leads to the paradox of the rational to keep the AR constantly inactivated in order to treat PCa. These observations however opened the option to treat PCa patients with AR antagonists and/or with androgens at supraphysiological levels. The latter is currently used in clinical trials in so-called bipolar androgen therapy (BAT). Notably, cellular senescence is induced by AR antagonists or agonist in both androgen-dependent and castration-resistant PCa (CRPC). Pathway analysis suggests a crosstalk between AR and the non-receptor tyrosine kinase Src-Akt/PKB and the PI3K-mTOR-autophagy signaling in mediating AR-induced cellular senescence in PCa. In this review, we summarize the current knowledge of therapeutic induction and intracellular pathways of AR-mediated cellular senescence.

scholarly journals Dendranthema zawadskii var. lucidum (Nakai) J.H. Park Extract Inhibits Cellular Senescence in Human Dermal Fibroblasts and Aging-Related Inflammation in Rats

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 801
Author(s):  
Jehun Choi ◽  
Gwi-Yeong Jang ◽  
Jeonghoon Lee ◽  
Hae-Young Chung ◽  
Hyung-Jun Noh ◽  
...  
Keyword(s):  
Cellular Senescence ◽  
Cell Cycle Progression ◽  
Inflammatory Responses ◽  
Dermal Fibroblast ◽  
Dermal Fibroblasts ◽  
Dependent Manner ◽  
Aged Rats ◽  
Age Related ◽  
Dendranthema Zawadskii ◽  
Beta Galactosidase

Senescence is the phenomenon by which physiological functions of organisms degenerate with time. Cellular senescence is marked by an inhibition of cell cycle progression. Beta-galactosidase accumulates in the lysosomes of aged cells. In this study, human dermal fibroblast cells (HDFs) were treated with 0.5 μM doxorubicin for 4 h to induce cellular senescence. Senescence-associated beta-galactosidase (SA-β-gal) activity was then measured 72 h after treatment with aerial parts of Dendranthema zawadskii var. lucidum (Nakai) J.H. Park (DZ) extract. Treatment with DZ extract significantly decreased SA-β-gal activity in a dose-dependent manner in HDFs. Additionally, DZ extract treatment reduced age-related oxidative stress and inflammation in the aortas of aged rats. The reactive oxygen species (ROS) levels in aortas of aged control rats were higher than those in young rats. However, DZ extract-fed aged rats showed significantly lower ROS levels than the aged control rats. When the aged rats were treated with DZ extract at either 0.2 or 1.0 mg∙kg−1∙day−1, NF-κB levels in aorta tissue decreased significantly compared to those in aorta tissue of the aged control rats without DZ treatment. In addition, DZ extract-fed aged rat aortas showed significant reductions in expression of iNOS and COX-2 induced by NF-κB translocation. Therefore, these results suggest that DZ effectively inhibited senescence-related NF-κB activation and inflammation. DZ extract may have a role in the prevention of the vascular inflammatory responses that occur during vascular aging.

scholarly journals CDC25B induces cellular senescence and correlates with tumor suppression in a p53-dependent manner

2021 ◽  
pp. 100564
Author(s):  
Ying-Chieh Chen ◽  
Hsi-Hsien Hsieh ◽  
Hsi-Chi Chang ◽  
Hsin-Chiao Wang ◽  
Wey-Jinq Lin ◽  
...  
Keyword(s):  
Cellular Senescence ◽  
Tumor Suppression ◽  
Dependent Manner

scholarly journals The Jekyll and Hyde of Cellular Senescence in Cancer

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 208
Author(s):  
Dilara Demirci ◽  
Bengisu Dayanc ◽  
Fatma Aybuke Mazi ◽  
Serif Senturk
Keyword(s):  
Cancer Cell ◽  
Cellular Senescence ◽  
Expression Profiles ◽  
Treatment Strategies ◽  
Gene Expression Profiles ◽  
Therapy Resistance ◽  
Disease Recurrence ◽  
Adverse Outcomes ◽  
Cell Senescence ◽  
Great Promise

Cellular senescence is a state of stable cell cycle arrest that can be triggered in response to various insults and is characterized by distinct morphological hallmarks, gene expression profiles, and the senescence-associated secretory phenotype (SASP). Importantly, cellular senescence is a key component of normal physiology with tumor suppressive functions. In the last few decades, novel cancer treatment strategies exploiting pro-senescence therapies have attracted considerable interest. Recent insight, however, suggests that therapy-induced senescence (TIS) elicits cell-autonomous and non-cell-autonomous implications that potentially entail detrimental consequences, reflecting the Jekyll and Hyde nature of cancer cell senescence. In essence, the undesirable manifestations that generally culminate in inflammation, cancer stemness, senescence reversal, therapy resistance, and disease recurrence are dictated by the persistent accumulation of senescent cells and the SASP. Thus, mitigating these pro-tumorigenic effects by eliminating these cells or inhibiting their SASP production holds great promise for developing innovative therapeutic strategies. In this review, we describe the fundamental aspects and dynamics of cancer cell senescence and summarize the comprehensive research on the adverse outcomes of TIS. Furthermore, we underline the rationale and motivation of emerging senotherapeutic modalities surrounding the removal of senescent cells and the SASP to help maximize the overall efficacy of cancer therapies.

scholarly journals Septin-dependent compartmentalization of the endoplasmic reticulum during yeast polarized growth

2005 ◽  
Vol 169 (6) ◽  
pp. 897-908 ◽  
Author(s):  
Cosima Luedeke ◽  
Stéphanie Buvelot Frei ◽  
Ivo Sbalzarini ◽  
Heinz Schwarz ◽  
Anne Spang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Membrane Proteins ◽  
Diffusion Barriers ◽  
Yeast Cells ◽  
Dependent Manner ◽  
Protein Diffusion ◽  
Ultrastructural Studies ◽  
Bud Neck ◽  
Er Membrane

Polarized cells frequently use diffusion barriers to separate plasma membrane domains. It is unknown whether diffusion barriers also compartmentalize intracellular organelles. We used photobleaching techniques to characterize protein diffusion in the yeast endoplasmic reticulum (ER). Although a soluble protein diffused rapidly throughout the ER lumen, diffusion of ER membrane proteins was restricted at the bud neck. Ultrastructural studies and fluorescence microscopy revealed the presence of a ring of smooth ER at the bud neck. This ER domain and the restriction of diffusion for ER membrane proteins through the bud neck depended on septin function. The membrane-associated protein Bud6 localized to the bud neck in a septin-dependent manner and was required to restrict the diffusion of ER membrane proteins. Our results indicate that Bud6 acts downstream of septins to assemble a fence in the ER membrane at the bud neck. Thus, in polarized yeast cells, diffusion barriers compartmentalize the ER and the plasma membrane along parallel lines.

Different sequence elements are required for function of the cauliflower mosaic virus polyadenylation site in Saccharomyces cerevisiae compared with in plants

1992 ◽  
Vol 12 (5) ◽  
pp. 2322-2330
Author(s):  
S Irniger ◽  
H Sanfaçon ◽  
C M Egli ◽  
G H Braus
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mosaic Virus ◽  
Cauliflower Mosaic Virus ◽  
Yeast Cells ◽  
Polyadenylation Site ◽  
Proper Function ◽  
Single Point Mutation ◽  
Dependent Manner ◽  
Sequence Element ◽  
Sequence Elements

We show that the polyadenylation site derived from the plant cauliflower mosaic virus (CaMV) is specifically functional in the yeast Saccharomyces cerevisiae. The mRNA 3' endpoints were mapped at the same position in yeast cells as in plants, and the CaMV polyadenylation site was recognized in an orientation-dependent manner. Mutational analysis of the CaMV 3'-end-formation signal revealed that multiple elements are essential for proper activity in yeast cells, including two upstream elements that are situated more than 100 and 43 to 51 nucleotides upstream of the poly(A) addition site and the sequences at or near the poly(A) addition site. A comparison of the sequence elements that are essential for proper function of the CaMV signal in yeast cells and plants showed that both organisms require a distal and a proximal upstream element but that these sequence elements are not identical in yeast cells and plants. The key element for functioning of the CaMV signal in yeast cells is the sequence TAGTATGTA, which is similar to a sequence previously proposed to act in yeast cells as a bipartite signal, namely, TAG ... TATGTA. Deletion of this sequence in the CaMV polyadenylation signal abolished 3'-end formation in yeast cells, and a single point mutation in this motif reduced the activity of the CaMV signal to below 15%. These results indicate that the bipartite sequence element acts as a signal for 3'-end formation in yeast cells but only together with other cis-acting elements.

scholarly journals Gold Nanoparticles Using Ecklonia stolonifera Protect Human Dermal Fibroblasts from UVA-Induced Senescence through Inhibiting MMP-1 and MMP-3

Marine Drugs ◽  
2020 ◽  
Vol 18 (9) ◽  
pp. 433
Author(s):  
Eun-Sook Jun ◽  
Yeong Jin Kim ◽  
Hyung-Hoi Kim ◽  
Sun Young Park
Keyword(s):  
Gold Nanoparticles ◽  
Cellular Senescence ◽  
Biological Activities ◽  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Dermal Fibroblasts ◽  
G1 Arrest ◽  
Human Dermal Fibroblasts ◽  
Ecklonia Stolonifera

The effect of gold nanoparticles (GNPs) synthesized in marine algae has been described in the context of skin, where they have shown potential benefit. Ecklonia stolonifera (ES) is a brown algae that belongs to the Laminariaceae family, and is widely used as a component of food and medicine due to its biological activities. However, the role of GNPs underlying cellular senescence in the protection of Ecklonia stolonifera gold nanoparticles (ES-GNPs) against UVA irradiation is less well known. Here, we investigate the antisenescence effect of ES-GNPs and the underlying mechanism in UVA-irradiated human dermal fibroblasts (HDFs). The DPPH and ABTS radical scavenging activity of ES extracts was analyzed. These analyses showed that ES extract has potent antioxidant properties. The facile and optimum synthesis of ES-GNPs was established using UV-vis spectra. The surface morphology and crystallinity of ES-GNPs were demonstrated using high resolution transmission electron microscopy (HR-TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). ES-GNPs presented excellent photocatalytic activity, as shown by the photo-degradation of methylene blue and rhodamine B. A cellular senescence model was established by irradiating HDFs with UVA. UVA-irradiated HDFs exhibited increased expression of senescence-associated β-galactosidase (SA-β-galactosidase). However, pretreatment with ES-GNPs resulted in reduced SA-β-galactosidase activity in UVA-irradiated HDFs. Intracellular ROS levels and G1 arrest in UVA-irradiated HDFs were checked against the background of ES-GNP treatment to investigate the antisenescence effects of ES-GNPs. The results showed that ES-GNPs significantly inhibit UVA-induced ROS levels and G1 arrest. Importantly, ES-GNPs significantly downregulated the transcription and translation of MMP (matrix metalloproteinases)-1/-3, which regulate cellular senescence in UVA-irradiated HDFs. These findings indicate that our optimal ES-GNPs exerted an antisenescence effect on UVA-irradiated HDFs by inhibiting MMP-1/-3 expression. Collectively, we posit that ES-GNPs may potentially be used to treat photoaging of the skin.

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