| 1. |
- Fontana, Jacopo M., et al.
(författare)
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Calcium oscillations triggered by cardiotonic steroids
- 2013
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 280:21, s. 5450-5455
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Forskningsöversikt (refereegranskat)abstract
- Na+, K+-ATPase (NKA) is well known for its function as an ion pump. Studies during the last decade have revealed an additional role for NKA as a signal transducer. In this brief review, we describe how cardiotonic steroids, which are highly specific NKA ligands, trigger slow Ca2+ oscillations by promoting the interaction between NKA and the inositol trisphosphate receptor, and how this Ca2+ signal activates the NF-B subunit p65 and increases the expression of the antiapoptotic factor Bcl-xL. The potential tissue-protective effects of this signal are discussed.
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| 2. |
- Fontana, Jacopo M., et al.
(författare)
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Spontaneous calcium activity in metanephric mesenchymal cells regulates branching morphogenesis in the embryonic kidney
- 2019
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Ingår i: The FASEB Journal. - : FEDERATION AMER SOC EXP BIOL. - 0892-6638 .- 1530-6860. ; 33:3, s. 4089-4096
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Tidskriftsartikel (refereegranskat)abstract
- The central role of calcium signaling during development of early vertebrates is well documented, but little is known about its role in mammalian embryogenesis. We have used immunofluorescence and time-lapse calcium imaging of cultured explanted embryonic rat kidneys to study the role of calcium signaling for branching morphogenesis. In mesenchymal cells, we recorded spontaneous calcium activity that was characterized by irregular calcium transients. The calcium signals were dependent on release of calcium from intracellular stores in the endoplasmic reticulum. Down-regulation of the calcium activity, both by blocking the sarco-endoplasmic reticulum Ca2+-ATPase and by chelating cytosolic calcium, resulted in retardation of branching morphogenesis and a reduced formation of primitive nephrons but had no effect on cell proliferation. We propose that spontaneous calcium activity contributes with a stochastic factor to the self-organizing process that controls branching morphogenesis, a major determinant of the ultimate number of nephrons in the kidney.Fontana, J. M., Khodus, G. R., Unnersjo-Jess, D., Blom, H., Aperia, A., Brismar, H. Spontaneous calcium activity in metanephric mesenchymal cells regulates branching morphogenesis in the embryonic kidney.
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| 3. |
- Fontana, Jacopo, et al.
(författare)
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Temporal calcium activity in metanephric mesenchyme cells regulates kidney branching morphogenesis
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The role of calcium signaling for development of early vertebrates is well documented, but little is known about its role in mammalian embryogenesis. We have used explanted embryonic rat kidneys to study the role of calcium for branching morphogenesis, a process that depends on reciprocal interaction between mesenchymal and epithelial ureteric bud cells. We recorded a spontaneous calcium activity characterized by stochastic and irregular calcium spikes, in the mesenchymal cells. This activity is due to calcium release from the endoplasmic reticulum (ER). Depletion of ER calcium stores results in down-regulation of the calcium activity, retardation of branching morphogenesis and formation of primitive nephrons, but has no effect on cell proliferation. We propose that the excretion of morphogenic factors that mediate the interaction between 26 the mesenchymal and epithelial cells, which initiate branching morphogenesis, is calcium dependent. In support of this we demonstrate expression of the calcium dependent excretory protein synaptotagmin1.
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| 4. |
- Li, Juan, et al.
(författare)
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Ouabain protects against adverse developmental programming of the kidney
- 2010
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 1, s. 42-
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Tidskriftsartikel (refereegranskat)abstract
- The kidney is extraordinarily sensitive to adverse fetal programming. Malnutrition, the most common form of developmental challenge, retards the formation of functional units, the nephrons. The resulting low nephron endowment increases susceptibility to renal injury and disease. Using explanted rat embryonic kidneys, we found that ouabain, the Na, K-ATPase ligand, triggers a calcium-nuclear factor-kappa B signal, which protects kidney development from adverse effects of malnutrition. To mimic malnutrition, kidneys were serum deprived for 24 h. This resulted in severe retardation of nephron formation and a robust increase in apoptosis. In ouabain-exposed kidneys, no adverse effects of serum deprivation were observed. Proof of principle that ouabain rescues development of embryonic kidneys exposed to malnutrition was obtained from studies on pregnant rats given a low-protein diet and treated with ouabain or vehicle throughout pregnancy. Thus, we have identified a survival signal and a feasible therapeutic tool to prevent adverse programming of kidney development.
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| 5. |
- Lundquist, Patrik, et al.
(författare)
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Barriers to the Intestinal Absorption of Four Insulin-Loaded Arginine-Rich Nanoparticles in Human and Rat
- 2022
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 16:9, s. 14210-14229
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Tidskriftsartikel (refereegranskat)abstract
- Peptide drugs and biologics provide opportunities for treatments of many diseases. However, due to their poor stability and permeability in the gastrointestinal tract, the oral bioavailability of peptide drugs is negligible. Nanoparticle formulations have been proposed to circumvent these hurdles, but systemic exposure of orally administered peptide drugs has remained elusive. In this study, we investigated the absorption mechanisms of four insulin-loaded arginine-rich nanoparticles displaying differing composition and surface characteristics, developed within the pan-European consortium TRANS-INT. The transport mechanisms and major barriers to nanoparticle permeability were investigated in freshly isolated human jejunal tissue. Cytokine release profiles and standard toxicity markers indicated that the nanoparticles were nontoxic. Three out of four nanoparticles displayed pronounced binding to the mucus layer and did not reach the epithelium. One nanoparticle composed of a mucus inert shell and cell-penetrating octarginine (ENCP), showed significant uptake by the intestinal epithelium corresponding to 28 ± 9% of the administered nanoparticle dose, as determined by super-resolution microscopy. Only a small fraction of nanoparticles taken up by epithelia went on to be transcytosed via a dynamin-dependent process. In situ studies in intact rat jejunal loops confirmed the results from human tissue regarding mucus binding, epithelial uptake, and negligible insulin bioavailability. In conclusion, while none of the four arginine-rich nanoparticles supported systemic insulin delivery, ENCP displayed a consistently high uptake along the intestinal villi. It is proposed that ENCP should be further investigated for local delivery of therapeutics to the intestinal mucosa.
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| 6. |
- Shrestha, Neha, et al.
(författare)
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The stimulation of GLP-1 secretion and delivery of GLP-1 agonists &ITvia&IT nanostructured lipid carriers
- 2018
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 10:2, s. 603-613
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Tidskriftsartikel (refereegranskat)abstract
- Nanoparticulate based drug delivery systems have been extensively studied to efficiently encapsulate and deliver peptides orally. However, most of the existing data mainly focus on the nanoparticles as a drug carrier, but the ability of nanoparticles having a biological effect has not been exploited. Herein, we hypothesize that nanostructured lipid carriers (NLCs) could activate the endogenous glucagon-like peptide-1 (GLP-1) secretion and also act as oral delivery systems for GLP-1 analogs (exenatide and liraglutide). NLCs effectively encapsulated the peptides, the majority of which were only released under the intestinal conditions. NLCs, with and without peptide encapsulation, showed effective induction of GLP-1 secretion in vitro from the enteroendocrinal L-cells (GLUTag). NLCs also showed a 2.9-fold increase in the permeability of exenatide across the intestinal cell monolayer. The intestinal administration of the exenatide and liraglutide loaded NLCs did not demonstrate any glucose lowering effect on normal mice. Further, ex vivo studies depicted that the NLCs mainly adhered to the mucus layer. In conclusion, this study demonstrates that NLCs need further optimization to overcome the mucosal barrier in the intestine; nonetheless, this study also presents a promising strategy to use a dual-action drug delivery nanosystem which synergizes its own biological effect and that of the encapsulated drug molecule.
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