A library of dendrimers was synthesized and optimized for targeted small interfering RNA (siRNA) delivery to different cell subpopulations within the liver. Using a combinatorial approach, a library ...of these nanoparticle-forming materials was produced wherein the free amines on multigenerational poly(amido amine) and poly(propylenimine) dendrimers were substituted with alkyl chains of increasing length, and evaluated for their ability to deliver siRNA to liver cell subpopulations. Interestingly, two lead delivery materials could be formulated in a manner to alter their tissue tropism within the liver-with formulations from the same material capable of preferentially delivering siRNA to 1)endothelial cells, 2)endothelial cells and hepatocytes, or 3)endothelial cells, hepatocytes, and tumor cells invivo. The ability to broaden or narrow the cellular destination of siRNA within the liver may provide a useful tool to address a range of liver diseases. Formulation control: Dendrimer derivatives for invivo siRNA delivery to liver endothelial cells, hepatocellular carcinoma cells, and/or hepatocytes are prepared from poly(amido amine) and poly(propylenimine) dendrimers substituted with alkyl chains of different lengths. Through formulation changes, these materials have the ability to broaden or narrow their targeted cellular subpopulation within the liver.
There is currently no known genetic disease linked to prolactin (Prl) or its receptor (PrlR) in humans. Given the essential role of this hormonal system in breast physiology, we reasoned that genetic ...anomalies of Prl/PrlR genes may be related to the occurrence of breast diseases with high proliferative potential. Multiple fibroadenomas (MFA) are benign breast tumors which appear most frequently in young women, including at puberty, when Prl has well-recognized proliferative actions on the breast. In a prospective study involving 74 MFA patients and 170 control subjects, we identified four patients harboring a heterozygous single nucleotide polymorphism in exon 6 of the PrlR gene, encoding Ile₁₄₆rightward arrowLeu substitution in its extracellular domain. This sole substitution was sufficient to confer constitutive activity to the receptor variant (PrlRI₁₄₆L), as assessed in three reconstituted cell models (Ba/F3, HEK293 and MCF-7 cells) by Prl-independent (i) PrlR tyrosine phosphorylation, (ii) activation of signal transducer and activator of transcription 5 (STAT5) signaling, (iii) transcriptional activity toward a Prl-responsive reporter gene, and (iv) cell proliferation and protection from cell death. Constitutive activity of PrlRI₁₄₆L in the breast sample from a patient was supported by increased STAT5 signaling. This is a unique description of a functional mutation of the PrlR associated with a human disease. Hallmarks of constitutive activity were all reversed by a specific PrlR antagonist, which opens potential therapeutic approaches for MFA, or any other disease that could be associated with this mutation in future.
The features of JAK-STAT signaling in liver cells are discussed in the current review. The role of this signaling cascade in carcinogenesis is accentuated. The possible involvement of this pathway ...and alteration of its elements are compared for normal cholangiocytes, cholangiocarcinoma predisposition and development. Prolactin and interleukin-6 are described in detail as the best studied examples. In addition, the non-classical nuclear translocation of cytokine receptors is discussed in terms of its possible implication to cholangiocarcinoma development.
Mitochondrial Ca2+ uptake via the uniporter is central to cell metabolism, signaling, and survival. Recent studies identified MCU as the uniporter’s likely pore and MICU1, an EF-hand protein, as its ...critical regulator. How this complex decodes dynamic cytoplasmic Ca2+ (Ca2+c) signals, to tune out small Ca2+c increases yet permit pulse transmission, remains unknown. We report that loss of MICU1 in mouse liver and cultured cells causes mitochondrial Ca2+ accumulation during small Ca2+c elevations but an attenuated response to agonist-induced Ca2+c pulses. The latter reflects loss of positive cooperativity, likely via the EF-hands. MICU1 faces the intermembrane space and responds to Ca2+c changes. Prolonged MICU1 loss leads to an adaptive increase in matrix Ca2+ binding, yet cells show impaired oxidative metabolism and sensitization to Ca2+ overload. Collectively, the data indicate that MICU1 senses the Ca2+c to establish the uniporter’s threshold and gain, thereby allowing mitochondria to properly decode different inputs.
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•MICU1 regulates the Ca2+ threshold and cooperativity of the mitochondrial uniporter•MICU1 faces the intermembrane space to sense cytoplasmic Ca2+•Loss of MICU1 initiates an adaptive increase in mitochondrial matrix Ca2+ binding•Yet decoding of Ca2+ signals is compromised, impairing ATP output and cell survival
A library of dendrimers was synthesized and optimized for targeted small interfering RNA (siRNA) delivery to different cell subpopulations within the liver. Using a combinatorial approach, a library ...of these nanoparticle‐forming materials was produced wherein the free amines on multigenerational poly(amido amine) and poly(propylenimine) dendrimers were substituted with alkyl chains of increasing length, and evaluated for their ability to deliver siRNA to liver cell subpopulations. Interestingly, two lead delivery materials could be formulated in a manner to alter their tissue tropism within the liver—with formulations from the same material capable of preferentially delivering siRNA to 1) endothelial cells, 2) endothelial cells and hepatocytes, or 3) endothelial cells, hepatocytes, and tumor cells in vivo. The ability to broaden or narrow the cellular destination of siRNA within the liver may provide a useful tool to address a range of liver diseases.
Formulierungskontrolle: Derivate aus Poly(amidoamin)‐ und Poly(propylenimin)‐Dendrimeren, die mit verschieden langen Alkylketten funktionalisiert sind, wurden für die In‐vitro‐Freisetzung von siRNA in Leberendothelzellen, hepatozellulären Krebszellen und/oder Hepatozyten hergestellt. Durch Änderung der Formulierung können diese Materialien gezielten Einfluss auf Zelluntergruppen in der Leber ausüben.
A library of dendrimers was synthesized and optimized for targeted small interfering RNA (siRNA) delivery to different cell subpopulations within the liver. Using a combinatorial approach, a library ...of these nanoparticle-forming materials was produced wherein the free amines on multigenerational poly(amido amine) and poly(propylenimine) dendrimers were substituted with alkyl chains of increasing length, and evaluated for their ability to deliver siRNA to liver cell subpopulations. Interestingly, two lead delivery materials could be formulated in a manner to alter their tissue tropism within the liver-with formulations from the same material capable of preferentially delivering siRNA to 1)endothelial cells, 2)endothelial cells and hepatocytes, or 3)endothelial cells, hepatocytes, and tumor cells invivo. The ability to broaden or narrow the cellular destination of siRNA within the liver may provide a useful tool to address a range of liver diseases.Original Abstract: Formulierungskontrolle: Derivate aus Poly(amidoamin)- und Poly(propylenimin)-Dendrimeren, die mit verschieden langen Alkylketten funktionalisiert sind, wurden fuer die In-vitro-Freisetzung von siRNA in Leberendothelzellen, hepatozellulaeren Krebszellen und/oder Hepatozyten hergestellt. Durch Aenderung der Formulierung konnen diese Materialien gezielten Einfluss auf Zelluntergruppen in der Leber ausueben.
The liver has a unique regenerative capability, which involves extensive remodelling of cell-cell and cell-matrix contacts. Here we study the role of integrins in mouse liver regeneration using ...Cre/loxP-mediated gene deletion or intravenous delivery of β1-integrin siRNA formulated into nanoparticles that predominantly target hepatocytes. We show that although short-term loss of β1-integrin has no obvious consequences for normal livers, partial hepatectomy leads to severe liver necrosis and reduced hepatocyte proliferation. Mechanistically, loss of β1-integrin in hepatocytes impairs ligand-induced phosphorylation of the epidermal growth factor and hepatocyte growth factor receptors, thereby attenuating downstream receptor signalling in vitro and in vivo. These results identify a crucial role and novel mechanism of action of β1-integrins in liver regeneration and demonstrate that protein depletion by nanoparticle-based delivery of specific siRNA is a powerful strategy to study gene function in the regenerating liver.
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