scholarly journals Late life metformin treatment limits cell survival and shortens lifespan by triggering an aging-associated failure of energy metabolism

2019 ◽  
Author(s):  
Lilia Espada ◽  
Alexander Dakhovnik ◽  
Prerana Chaudhari ◽  
Asya Martirosyan ◽  
Laura Miek ◽  
...  
Keyword(s):  
Mitochondrial Dysfunction ◽  
Cell Survival ◽  
Dietary Restriction ◽  
Early Life ◽  
Late Life ◽  
List Type ◽  
Metformin Treatment ◽  
Atp Levels

SummaryThe diabetes drug metformin is to be clinically tested in aged humans to achieve health span extension, but little is known about responses of old non-diabetic individuals to this drug. By in vitro and in vivo tests we found that metformin shortens life span and limits cell survival when provided in late life, contrary to its positive early life effects. Mechanistically, metformin exacerbates aging-associated mitochondrial dysfunction towards respiratory failure, aggravated by the inability of old cells to upregulate glycolysis in response to metformin, leading to ATP exhaustion. The beneficial dietary restriction effect of metformin on lipid reserves is abrogated in old animals, contributing to metabolic failure, while ectopic stabilization of cellular ATP levels alleviates late life metformin toxicity in vitro and in vivo. The toxicity is also suspended in nematodes carrying diabetes-like insulin receptor insufficiency and showing prolonged resilience to metabolic stress induced by metformin. In sum, we uncovered an alarming metabolic decay triggered by metformin in late life which may limit its benefits for non-diabetic elderly patients. Novel regulators of life extension by metformin are also presented.HighlightsLate life metformin treatment limits cell survival and shortens lifespan.Metformin exacerbates aging-associated mitochondrial dysfunction causing fatal ATP exhaustion.Old cells fail to upregulate glycolysis as a compensatory response to metformin.The dietary restriction (DR) mimetic response to metformin is abrogated in old animals.PKA and not AMPK pathway instigates the early life DR response to metformin.Stabilization of cellular ATP levels alleviates late life metformin toxicity in vitro and in vivo.

scholarly journals Self-assembly of multi-component mitochondrial nucleoids via phase separation

2019 ◽  
Author(s):  
Marina Feric ◽  
Tyler G. Demarest ◽  
Jane Tian ◽  
Deborah L. Croteau ◽  
Vilhelm A. Bohr ◽  
...  
Keyword(s):  
Phase Separation ◽  
Mitochondrial Dysfunction ◽  
Self Assembly ◽  
Size Control ◽  
Premature Aging ◽  
List Type ◽  
Mitochondrial Nucleoids ◽  
Hutchinson Gilford Progeria Syndrome

SummaryMitochondria contain an autonomous and spatially segregated genome. The organizational unit of their genome is the nucleoid, which consists of mitochondrial DNA (mtDNA) and associated architectural proteins. Here, we show that phase separation is the primary physical mechanism for assembly and size-control of the mitochondrial nucleoid. The major mtDNA-binding protein TFAM spontaneously phase separates in vitro via weak, multivalent interactions into viscoelastic droplets with slow internal dynamics. In combination, TFAM and mtDNA form multiphase, gel-like structures in vitro, which recapitulate the in vivo dynamic behavior of mt-nucleoids. Enlarged, phase-separated, yet transcriptionally active, nucleoids are present in mitochondria from patients with the premature aging disorder Hutchinson-Gilford Progeria Syndrome (HGPS) and are associated with mitochondrial dysfunction. These results point to phase separation as an evolutionarily conserved mechanism of genome organization.HighlightsMitochondrial genomes are organized by phase separation.The main packaging protein TFAM and mtDNA combine to form viscoelastic, multiphase droplets in vitro.Mitochondrial nucleoids exhibit phase behavior in vivo, including dynamic rearrangements and heterogenous organization.Coalescence and enlargement of mt-nucleoids occur upon loss of mitochondrial homeostasis as well as in prematurely aged cells and are associated with mitochondrial dysfunction.

LACK OF EFFECT OF CORTICOSTEROIDS ON THE IN VIVO DISAPPEARANCE OF SULFHYDRYL-INHIBITED AND ANTIBODY-COATED ERYTHROCYTES

1964 ◽  
Vol 47 (3_Suppl) ◽  
pp. S28-S36
Author(s):  
Kailash N. Agarwal
Keyword(s):  
Red Cells ◽  
List Type ◽  
Red Cell

ABSTRACT Red cells were incubated in vitro with sulfhydryl inhibitors and Rhantibody with and without prior incubation with prednisolone-hemisuccinate. These erythrocytes were labelled with Cr51 and P32 and their disappearance in vivo after autotransfusion was measured. Prior incubation with prednisolone-hemisuccinate had no effect on the rate of red cell disappearance. The disappearance of the cells was shown to take place without appreciable intravascular destruction.

Research on The Effect of Amyloid beta on Mitochondrial Dysfunction In vivo and In vitro*

2010 ◽  
Vol 37 (2) ◽  
pp. 154-160 ◽  
Author(s):  
Ling-Ling LIU ◽  
Bai-Yang SHENG ◽  
Kai GONG ◽  
Nan-Ming ZHAO ◽  
Xiu-Fang ZHANG ◽  
...  
Keyword(s):  
Mitochondrial Dysfunction ◽  
Amyloid Beta

scholarly journals Macropinocytosis requires Gal-3 in a subset of patient-derived glioblastoma stem cells

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Laetitia Seguin ◽  
Soline Odouard ◽  
Francesca Corlazzoli ◽  
Sarah Al Haddad ◽  
Laurine Moindrot ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Survival ◽  
Small Gtpases ◽  
Molecular Signature ◽  
Carbohydrate Binding ◽  
Pancreatic Cancers ◽  
Galectin 3 ◽  
Pharmacologic Inhibition

AbstractRecently, we involved the carbohydrate-binding protein Galectin-3 (Gal-3) as a druggable target for KRAS-mutant-addicted lung and pancreatic cancers. Here, using glioblastoma patient-derived stem cells (GSCs), we identify and characterize a subset of Gal-3high glioblastoma (GBM) tumors mainly within the mesenchymal subtype that are addicted to Gal-3-mediated macropinocytosis. Using both genetic and pharmacologic inhibition of Gal-3, we showed a significant decrease of GSC macropinocytosis activity, cell survival and invasion, in vitro and in vivo. Mechanistically, we demonstrate that Gal-3 binds to RAB10, a member of the RAS superfamily of small GTPases, and β1 integrin, which are both required for macropinocytosis activity and cell survival. Finally, by defining a Gal-3/macropinocytosis molecular signature, we could predict sensitivity to this dependency pathway and provide proof-of-principle for innovative therapeutic strategies to exploit this Achilles’ heel for a significant and unique subset of GBM patients.

scholarly journals Osteoblast-Derived Paracrine and Juxtacrine Signals Protect Disseminated Breast Cancer Cells from Stress

Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1366
Author(s):  
Russell Hughes ◽  
Xinyue Chen ◽  
Natasha Cowley ◽  
Penelope D. Ottewell ◽  
Rhoda J. Hawkins ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Survival ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Breast Cancer Cells ◽  
Metastatic Breast ◽  
Accessory Cell ◽  
Cancer Cell Survival

Metastatic breast cancer in bone is incurable and there is an urgent need to develop new therapeutic approaches to improve survival. Key to this is understanding the mechanisms governing cancer cell survival and growth in bone, which involves interplay between malignant and accessory cell types. Here, we performed a cellular and molecular comparison of the bone microenvironment in mouse models representing either metastatic indolence or growth, to identify mechanisms regulating cancer cell survival and fate. In vivo, we show that regardless of their fate, breast cancer cells in bone occupy niches rich in osteoblastic cells. As the number of osteoblasts in bone declines, so does the ability to sustain large numbers of breast cancer cells and support metastatic outgrowth. In vitro, osteoblasts protected breast cancer cells from death induced by cell stress and signaling via gap junctions was found to provide important juxtacrine protective mechanisms between osteoblasts and both MDA-MB-231 (TNBC) and MCF7 (ER+) breast cancer cells. Combined with mathematical modelling, these findings indicate that the fate of DTCs is not controlled through the association with specific vessel subtypes. Instead, numbers of osteoblasts dictate availability of protective niches which breast cancer cells can colonize prior to stimulation of metastatic outgrowth.

scholarly journals ApoE4 (Δ272–299) induces mitochondrial‐associated membrane formation and mitochondrial impairment by enhancing GRP75-modulated mitochondrial calcium overload in neuron

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tao Liang ◽  
Weijian Hang ◽  
Jiehui Chen ◽  
Yue Wu ◽  
Bin Wen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Er Stress ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Calcium Transport ◽  
Calcium Overload ◽  
Mitochondrial Calcium ◽  
Mitochondrial Impairment

Abstract Background Apolipoprotein E4 (apoE4) is a major genetic risk factor of Alzheimer’s disease. Its C-terminal-truncated apoE4 (Δ272–299) has neurotoxicity by affecting mitochondrial respiratory function. However, the molecular mechanism(s) underlying the action of apoE4 (Δ272–299) in mitochondrial function remain poorly understood. Methods The impact of neuronal apoE4 (Δ272–299) expression on ER stress, mitochondrial-associated membrane (MAM) formation, GRP75, calcium transport and mitochondrial impairment was determined in vivo and in vitro. Furthermore, the importance of ER stress or GRP75 activity in the apoE4 (Δ272–299)-promoted mitochondrial dysfunction in neuron was investigated. Results Neuronal apoE4 (Δ272–299) expression induced mitochondrial impairment by inducing ER stress and mitochondrial-associated membrane (MAM) formation in vivo and in vitro. Furthermore, apoE4 (Δ272–299) expression promoted GRP75 expression, mitochondrial dysfunction and calcium transport into the mitochondria in neuron, which were significantly mitigated by treatment with PBA (an inhibitor of ER stress), MKT077 (a specific GRP75 inhibitor) or GRP75 silencing. Conclusions ApoE4 (Δ272–299) significantly impaired neuron mitochondrial function by triggering ER stress, up-regulating GRP75 expression to increase MAM formation, and mitochondrial calcium overload. Our findings may provide new insights into the neurotoxicity of apoE4 (Δ272–299) against mitochondrial function and uncover new therapeutic targets for the intervention of Alzheimer’s disease.

scholarly journals Reduced High-Dose Radiation-Induced Residual Genotoxic Damage by Induction of Radioadaptive Response and Prophylactic Mild Dietary Restriction in Mice

Dose-Response ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 155932582098216
Author(s):  
Bing Wang ◽  
Kaoru Tanaka ◽  
Takanori Katsube ◽  
Kouichi Maruyama ◽  
Yasuharu Ninomiya ◽  
...  
Keyword(s):  
Dietary Restriction ◽  
High Dose ◽  
Cancer Treatments ◽  
Hematopoietic Stem ◽  
Beneficial Effects ◽  
Radiation Induced ◽  
Potential Strategy ◽  
Higher Doses

Radioadaptive response (RAR) describes a phenomenon in a variety of in vitro and in vivo systems that a low-dose of priming ionizing radiation (IR) reduces detrimental effects of a subsequent challenge IR at higher doses. Among in vivo investigations, studies using the mouse RAR model (Yonezawa Effect) showed that RAR could significantly extenuate high-dose IR-induced detrimental effects such as decrease of hematopoietic stem cells and progenitor cells, acute radiation hematopoietic syndrome, genotoxicity and genomic instability. Meanwhile, it has been demonstrated that diet intervention has a great impact on health, and dietary restriction shows beneficial effects on numerous diseases in animal models. In this work, by using the mouse RAR model and mild dietary restriction (MDR), we confirmed that combination of RAR and MDR could more efficiently reduce radiogenotoxic damage without significant change of the RAR phenotype. These findings suggested that MDR may share some common pathways with RAR to activate mechanisms consequently resulting in suppression of genotoxicity. As MDR could also increase resistance to chemotherapy and radiotherapy in normal cells, we propose that combination of MDR, RAR, and other cancer treatments (i.e., chemotherapy and radiotherapy) represent a potential strategy to increase the treatment efficacy and prevent IR risk in humans.

scholarly journals Mfn2 Overexpression Attenuates MPTP Neurotoxicity In Vivo

2021 ◽  
Vol 22 (2) ◽  
pp. 601
Author(s):  
Fanpeng Zhao ◽  
Quillan Austria ◽  
Wenzhang Wang ◽  
Xiongwei Zhu
Keyword(s):  
Mitochondrial Dysfunction ◽  
Mitochondrial Dynamics ◽  
Significant Loss ◽  
Critical Event ◽  
Mitochondrial Fragmentation ◽  
Wild Type Littermate ◽  
Littermate Control ◽  
Mptp Administration

Mitochondrial dysfunction represents a critical event in the pathogenesis of Parkinson’s disease (PD). Increasing evidence demonstrates that disturbed mitochondrial dynamics and quality control play an important role in mitochondrial dysfunction in PD. Our previous study demonstrated that MPP+ induces mitochondrial fragmentation in vitro. In this study, we aimed to assess whether blocking MPTP-induced mitochondrial fragmentation by overexpressing Mfn2 affords neuroprotection in vivo. We found that the significant loss of dopaminergic neurons in the substantia nigra (SN) induced by MPTP treatment, as seen in wild-type littermate control mice, was almost completely blocked in mice overexpressing Mfn2 (hMfn2 mice). The dramatic reduction in dopamine neuronal fibers and dopamine levels in the striatum caused by MPTP administration was also partially inhibited in hMfn2 mice. MPTP-induced oxidative stress and inflammatory response in the SN and striatum were significantly alleviated in hMfn2 mice. The impairment of motor function caused by MPTP was also blocked in hMfn2 mice. Overall, our work demonstrates that restoration of mitochondrial dynamics by Mfn2 overexpression protects against neuronal toxicity in an MPTP-based PD mouse model, which supports the modulation of mitochondrial dynamics as a potential therapeutic target for PD treatment.

Abstract 558: Microchanneled Polysaccharide Hydrogel Laden With Endothelial Cells and Mesenchymal Stem Cells With VEGF Facilitate Formation of Vascular Structures and Are Effective for Repairing Tissue Ischemia

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Sangho Lee ◽  
Min Kyung Lee ◽  
Hyunjoon Kong ◽  
Young-sup Yoon
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Mesenchymal Stem Cells ◽  
Cell Survival ◽  
Vascular Structure ◽  
Hindlimb Ischemia ◽  
Alginate Hydrogel ◽  
Vessel Formation

Various hydrogels are used to create vascular structure in vitro or to improve cell engraftment to overcome low cell survival in vivo, a main hurdle for bare cell therapy Recently we developed a modified alginate hydrogel within which microchannels are aligned to guide the direction and spatial organization of loaded cells. We investigated whether these cell constructs in which HUVECs and human mesenchymal stem cells (hMSCs) are co-loaded in this novel microchanneled hydrogel facilitate formation of vessels in vitro and in vivo, and enhance recovery of hindlimb ischemia. We crafted a modified alginate hydrogel which has microchannels, incorporates a cell adhesion peptide RGD, and was encapsulated with VEGF. We then compared vascular structure formation between the HUVEC only (2 x 105 cells) group and the HUVEC plus hMSC group. In the HUVEC+hMSC group, we mixed HUVECs and hMSCs at the ratio of 3:1. For cell tracking, we labeled HUVECs with DiO, a green fluorescence dye. After loading cells into the microchannels of the hydrogel, these constructs were cultured for seven days and were examined by confocal microscopy. In the HUVEC only group, HUVECs stands as round shaped cells without forming tubular structures within the hydrogel. However, in the HUVEC+hMSC group, HUVECs were stretched out and connected with each other, and formed vessel-like structure following pre-designed microchannels. These results suggested that hMSCs play a critical role for vessel formation by HUVECs. We next determined their in vivo effects using a mouse hindlimb ischemia model. We found that engineered HUVEC+hMSC group showed significantly higher perfusion over 4 weeks compared to the engineered HUVEC only group or bare cell (HUVEC) group. Confocal microscopic analysis of harvested tissues showed more robust vessel formation within and outside of the cell constructs and longer term cell survival in HUVEC+hMSC group compared to the other groups. In conclusion, this novel microchanneled alginate hydrogel facilitates aligned vessel formation of endothelial cells when combined with MSCs. This vessel-embedded hydrogel constructs consisting of HUVECs and MSCs contribute to perfusable vessel formation, prolong cell survival in vivo, and are effective for recovering limb ischemia.

Abstract 5368: Igf +hgf Enhance Sca-1 + /cd31 − Cell Therapy in Hearts with Postinfarction Lv Remodeling

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Xiaohong Wang ◽  
Elizabeth Braunlin ◽  
Qingsong Hu ◽  
Joseph Lee ◽  
Qinglu Li ◽  
...  
Keyword(s):  
Growth Factor ◽  
Cell Survival ◽  
Cell Transplantation ◽  
Cellular Therapy ◽  
Contractile Function ◽  
Lv Function ◽  
Beneficial Effects ◽  
Myocardial Bioenergetics

Insulin-like growth factor 1 (IGF-1) and hepatocyte growth factor (HGF) are two potent cell survival factors in response to hypoxia and oxidative stress. We have previously shown that transplantation of Sca-1 + /CD31 − cells can improve LV function in hearts with acute myocardial infarction (AMI) although the engraftment rate was low. We hypothesized that supplementation of IGF-1 and HGF at delivery of cellular therapy can enhance the beneficial effects of Sca-1 + /CD31 − cells in the injured heart by increasing engraftment rate and endogenous cardiac cell survival. Adenovirus nuclear LacZ-labeled Sca-1 + /CD31 − cells (1x10 6 ) were injected into the ischemic area after LAD ligation in BalbC mice. Recombinant mouse IGF-1+HGF (100ng) was added to the cell suspension prior to the injection. The LV function (ECHO) and in vivo myocardial bioenergetics ( 31 P-NMR spectroscopy) were assessed 4 weeks after AMI and cell transplantation. Normal mice (Normal, n=6), and 2 control groups of LAD ligation (MI, n=6), and MI plus Sca-1 + /CD31 − cell transplantation (Cell, n=6), were compared to AMI mice with Sca-1 + /CD31 − cells transplantation plus IGF-1+HGF (Cell+IGF-1+HGF, n=6). Sca-1 + /CD31 − cells formed viable grafts and improved LV contractile function (EF: Control, 53.3+/−3.2; MI, 18.9+/−3.9; Cell, 29.1+/−5.1, p<0.05) and myocardial bioenergetics (PCr/ATP: Control, 2.13+/−0.09; MI, 1.21+/−0.09; Cell, 1.72+/−0.12; p<0.01). IGF+HGF significantly further enhanced the benefits of the cell transplantation as evidenced by significantly increased EF to 38.3+/−3.1% (p<0.05), which was accompanied by a higher cell engraftment rate (p<0.05). Using the in vitro co culture of Sca-1 + /CD31 − cells with HL-1 cells labeled by Vybrant CFDA SE cell tracer kit, we observed both IGF+HGF and Sca-1 + /CD31 − cells can inhibit TNFα and hypoxia induced HL-1 cell apoptosis (Control, 7+/−1%; TNFα, 24+/−1%; IGF+HGF+TNFα, 10+/−1%; n=6, P<0.001) and caspase 3 expression. These data demonstrate that IGF-1+HGF could serve as an adjuvant to cell transplantation for myocardial restoration.

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