1. Isolation of live cells from different mice tissues up to nine days after deathMetka Voga, Ana Pleterski, Gregor Majdič, 2021, izvirni znanstveni članek Opis: Some limited reports suggest that cells can survive in the cadavers for much longer than it was previously thought. In our study we explored how time after death, tissue type (muscle, brain and adipose tissue), storage temperature of cadavers (4 °C or at room temperature) and form of tissue storage (stored as cadavers or tissue pieces in phosphate buffered saline) affect the success of harvesting live cells from mice after death. Cells were isolated from dead tissues and grown in standard conditions. Some cells were used for RNA extraction and RT² Profiler™ PCR Array for cell lineage identification was performed to establish which lineages the cells obtained from post mortem tissues belong to. Results of our study showed that viable cells can be regularly isolated from muscle and brain tissue 3 days post mortem and with difficulty up to 6 days post mortem. Viable cells from brain tissue can be isolated up to 9 days post mortem. No cells were isolated from adipose tissue except immediately after death. In all instances viable cells were isolated only when tissues were stored at 4 °C. Tissue storage did not affect cell isolation. Isolated cells were progenitors from different germ layers. Our results show that live cells could be obtained from mouse cadavers several days after death. Ključne besede: mouse, cadaver, stem cells, brain, muscle, adipose tissue Objavljeno v DKUM: 21.10.2024; Ogledov: 0; Prenosov: 2 Celotno besedilo (1,48 MB) Gradivo ima več datotek! Več... |
2. Glucose-stimulated calcium dynamics in beta cells from male C57BL/6J, C57BL/6N, and NMRI mice : a comparison of activation, activity, and deactivation properties in tissue slicesViljem Pohorec, Lidija Križančić Bombek, Maša Skelin, Jurij Dolenšek, Andraž Stožer, 2022, izvirni znanstveni članek Opis: Although mice are a very instrumental model in islet beta cell research, possible phenotypic differences between strains and substrains are largely neglected in the scientific community. In this study, we show important phenotypic differences in beta cell responses to glucose between C57BL/6J, C57BL/6N, and NMRI mice, i.e., the three most commonly used strains. High-resolution multicellular confocal imaging of beta cells in acute pancreas tissue slices was used to measure and quantitatively compare the calcium dynamics in response to a wide range of glucose concentrations. Strain- and substrain-specific features were found in all three phases of beta cell responses to glucose: a shift in the dose-response curve characterizing the delay to activation and deactivation in response to stimulus onset and termination, respectively, and distinct concentration-encoding principles during the plateau phase in terms of frequency, duration, and active time changes with increasing glucose concentrations. Our results underline the significance of carefully choosing and reporting the strain to enable comparison and increase reproducibility, emphasize the importance of analyzing a number of different beta cell physiological parameters characterizing the response to glucose, and provide a valuable standard for future studies on beta cell calcium dynamics in health and disease in tissue slices. Ključne besede: beta cell, mouse models, calcium imaging, glucose-dependence, tissue slice Objavljeno v DKUM: 15.07.2024; Ogledov: 148; Prenosov: 21 Celotno besedilo (4,45 MB) Gradivo ima več datotek! Več... |
3. Fine-tuning cardiac insulin-like growth factor 1 receptor signaling to promote health and longevityMahmoud Abdellatif, Viktoria Herbst, Alexander Martin Heberle, Alina Humnig, Tobias Pendl, Sylvère Durand, Giulia Cerrato, Sebastian J Hofer, Moydul Islam, Julia Voglhuber, Simon Sedej, 2022, izvirni znanstveni članek Opis: Background: The insulin-like growth factor 1 (IGF1) pathway is a key regulator of cellular metabolism and aging. Although its inhibition promotes longevity across species, the effect of attenuated IGF1 signaling on cardiac aging remains controversial.
Methods: We performed a lifelong study to assess cardiac health and lifespan in 2 cardiomyocyte-specific transgenic mouse models with enhanced versus reduced IGF1 receptor (IGF1R) signaling. Male mice with human IGF1R overexpression or dominant negative phosphoinositide 3-kinase mutation were examined at different life stages by echocardiography, invasive hemodynamics, and treadmill coupled to indirect calorimetry. In vitro assays included cardiac histology, mitochondrial respiration, ATP synthesis, autophagic flux, and targeted metabolome profiling, and immunoblots of key IGF1R downstream targets in mouse and human explanted failing and nonfailing hearts, as well.
Results: Young mice with increased IGF1R signaling exhibited superior cardiac function that progressively declined with aging in an accelerated fashion compared with wild-type animals, resulting in heart failure and a reduced lifespan. In contrast, mice with low cardiac IGF1R signaling exhibited inferior cardiac function early in life, but superior cardiac performance during aging, and increased maximum lifespan, as well. Mechanistically, the late-life detrimental effects of IGF1R activation correlated with suppressed autophagic flux and impaired oxidative phosphorylation in the heart. Low IGF1R activity consistently improved myocardial bioenergetics and function of the aging heart in an autophagy-dependent manner. In humans, failing hearts, but not those with compensated hypertrophy, displayed exaggerated IGF1R expression and signaling activity.
Conclusions: Our findings indicate that the relationship between IGF1R signaling and cardiac health is not linear, but rather biphasic. Hence, pharmacological inhibitors of the IGF1 pathway, albeit unsuitable for young individuals, might be worth considering in older adults. Ključne besede: aging, autophagy, cardiomyopathies, insulin-like growth factor 1, mitochondria, mouse, phosphatidylinositol 3-kinases Objavljeno v DKUM: 11.08.2023; Ogledov: 495; Prenosov: 47 Celotno besedilo (3,06 MB) Gradivo ima več datotek! Več... |
4. Spermidine overrides INSR (insulin receptor)-IGF1R (insulin-like growth factor 1 receptor)-mediated inhibition of autophagy in the aging heartMahmoud Abdellatif, Frank Madeo, Guido Kroemer, Simon Sedej, 2022, drugi znanstveni članki Opis: Although attenuated IGF1R (insulin-like growth factor 1 receptor) signaling has long been viewed to promote longevity in model organisms, adverse effects on the heart have been the subject of major concern. We observed that IGF1R is overexpressed in cardiac tissues from patients with end-stage non-ischemic heart failure, coupled to the activation of the IGF1R downstream effector AKT/protein kinase B and inhibition of ULK1 (unc-51 like autophagy activating kinase 1). Transgenic overexpression of human IGF1R in cardiomyocytes from mice initially induces physiological cardiac hypertrophy and superior function, but later in life confers a negative impact on cardiac health, causing macroautophagy/autophagy inhibition as well as impaired oxidative phosphorylation, thus reducing life expectancy. Treatment with the autophagy inducer and caloric restriction mimetic spermidine ameliorates most of these IGF1R-induced cardiotoxic effects in vivo. Moreover, inhibition of IGF1R signaling by means of a dominant-negative phosphoinositide 3-kinase (PI3K) mutant induces cardioprotective autophagy, restores myocardial bioenergetics and improves late-life survival. Hence, our results demonstrate that IGF1R exerts a dual biphasic impact on cardiac health, and that autophagy mediates the late-life geroprotective effects of IGF1R inhibition in the heart. Ključne besede: heart failure, IGF1R, PI3K, human, insulin signaling, longevity, mitochondrial dysfunction, mouse Objavljeno v DKUM: 08.08.2023; Ogledov: 335; Prenosov: 40 Celotno besedilo (619,72 KB) Gradivo ima več datotek! Več... |
5. Functional connectivity in islets of Langerhans from mouse pancreas tissue slicesAndraž Stožer, Marko Gosak, Jurij Dolenšek, Matjaž Perc, Marko Marhl, Marjan Rupnik, Dean Korošak, 2013, izvirni znanstveni članek Opis: We propose a network representation of electrically coupled beta cells in islets of Langerhans. Beta cells are functionally connected on the basis of correlations between calcium dynamics of individual cells, obtained by means of confocal laser-scanning calcium imaging in islets from acute mouse pancreastissue slices. Obtained functional networks are analyzed in the light of known structural and physiological properties of islets. Focusing on the temporal evolution of the network under stimulation with glucose, we show thatthe dynamics are more correlated under stimulation than under non-stimulated conditions and that the highest overall correlation, largely independent of Euclidean distances between cells, is observed in the activation and deactivation phases when cells are driven by the external stimulus. Moreover, we find that the range of interactions in networks during activity shows a clear dependence on the Euclidean distance, lending support to previous observations that beta cells are synchronized via calcium waves spreading throughout islets. Most interestingly, the functional connectivity patterns between beta cells exhibit small-world properties, suggesting that beta cells do not form a homogeneous geometric network but are connected in a functionally more efficient way. Presented results provide support for the existing knowledge of beta cell physiology from a network perspective and shedimportant new light on the functional organization of beta cell syncitia whose structural topology is probably not as trivial as believed so far. Ključne besede: islets of Langerhans, mouse pancreas Objavljeno v DKUM: 16.06.2017; Ogledov: 1540; Prenosov: 417 Celotno besedilo (798,57 KB) Gradivo ima več datotek! Več... |
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