Rosiglitazone Promotes AQP2 Plasma Membrane Expression In Renal Cells Via a Ca2+-Dependent/cAMP-Independent Mechanism

Procino, Giuseppe; Gerbino, Andrea; Milano, Serena; Nicoletti, Maria Celeste; Mastrofrancesco, Lisa; Carmosino, Monica; Svelto, María

doi:10.1159/000373933

Cited by 27 publications

(27 citation statements)

References 79 publications

(87 reference statements)

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“…During dehydration and hypernatremia, AVP is secreted by the pituitary gland and binds type-2 receptor (V2R) at the basolateral membrane of renal collecting duct principal cells [1-4]. Activation of the cAMP/PKA signal transduction pathway stimulates the translocation of AQP2-bearing vesicles to the apical plasma membrane increasing luminal permeability [5-7].…”

Section: Introductionmentioning

confidence: 99%

AQP2 Abundance is Regulated by the E3-Ligase CHIP Via HSP70

Centrone

Ranieri

Mise

et al. 2017

Cell Physiol Biochem

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Background/Aims: AQP2 expression is mainly controlled by vasopressin-dependent changes in protein abundance which is in turn regulated by AQP2 ubiquitylation and degradation, however the proteins involved in these processes are largely unknown. Here, we investigated the potential role of the CHIP E3 ligase in AQP2 regulation. Methods: MCD4 cells and kidney slices were used to study the involvement of the E3 ligase CHIP on AQP2 protein abundance by cell homogenization and immunoprecipitation followed by immunoblotting. Results: We found that AQP2 complexes with CHIP in renal tissue. Expression of CHIP increased proteasomal degradation of AQP2 and HSP70 abundance, a molecular signature of HSP90 inhibition. Increased HSP70 level, secondary to CHIP expression, promoted ERK signaling resulting in increased AQP2 phosphorylation at S261. Phosphorylation of AQP2 at S256 and T269 were instead downregulated. Next, we investigated HSP70 interaction with AQP2, which is important for endocytosis. Compared with AQP2-wt, HSP70 binding decreased in AQP2-S256D and AQP2-S256D-S261D, while increased in AQP2-S256D-S261A. Surprisingly, expression of CHIP-delUbox, displaying a loss of E3 ligase activity, still induced AQP2 degradation, indicating that CHIP does not ubiquitylate and degrade AQP2 itself. Conversely, the AQP2 half-life was increased upon the expression of CHIP-delTPR a domain which binds Hsc70/HSP70 and HSP90. HSP70 has been reported to bind other E3 ligases such as MDM2. Notably, we found that co-expression of CHIP and MDM2 increased AQP2 degradation, whereas co-expression of CHIP with MDM2-delRING, an inactive form of MDM2, impaired AQP2 degradation. Conclusion: Our findings indicate CHIP as a master regulator of AQP2 degradation via HSP70 that has dual functions: (1) as chaperone for AQP2 and (2) as an anchoring protein for MDM2 E3 ligase, which is likely to be involved in AQP2 degradation.

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Section: Introductionmentioning

confidence: 99%

AQP2 Abundance is Regulated by the E3-Ligase CHIP Via HSP70

Centrone

Ranieri

Mise

et al. 2017

Cell Physiol Biochem

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“…Assadi and Sharbaf reported a case of X-linked NDI treated with sildenafil; treatment decreased urine volume and enhanced urine osmolality compared with the combination of HTCZ, amiloride, and indomethacin (21). Rosiglitazone was shown to upregulate AQP2 and NKCC2 in MCD4 cells by a Ca-dependent/cAMP-independent pathway (22). Here, we presented the effects of AMPK activation as a novel approach.…”

Section: Discussionmentioning

confidence: 99%

Metformin improves urine concentration in rodents with nephrogenic diabetes insipidus

Efe¹,

Klein²,

LaRocque³

et al. 2016

JCI Insight

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Urine concentration is regulated by vasopressin. Congenital nephrogenic diabetes insipidus (NDI) is caused by vasopressin type 2 receptor (V2R) mutations. We studied whether metformin could improve urine concentration in rodent models of congenital NDI by stimulating AMPK. To block the V2R in rats, tolvaptan (10 mg/kg/d) was given by oral gavage with or without metformin (800 mg/ kg/d). Control rats received vehicle with or without metformin. Tamoxifen-induced V2R KO mice were given metformin (600 mg/kg) or vehicle twice daily. Urine osmolality in tolvaptan-treated rats (1,303 ± 126 mOsM) was restored to control levels by metformin (2,335 ± 273 mOsM) within 3 days and was sustained for up to 10 days. Metformin increased protein abundance of inner medullary urea transporter UT-A1 by 61% and aquaporin 2 (AQP2) by 44% in tolvaptan-treated rats, and immunohistochemistry showed increased membrane accumulation of AQP2 with acute and chronic AMPK stimulation. Outer medullary Na+-K+-2Cl− cotransporter 2 (NKCC2) abundance increased (117%) with AMPK stimulation in control rats but not in V2R-blocked rats. Metformin increased V2R KO mouse urine osmolality within 3 hours, and the increase persisted for up to 12 hours. Metformin increased AQP2 in the V2R KO mice similar to the tolvaptan-treated rats. These results indicate that AMPK activators, such as metformin, might provide a promising treatment for congenital NDI.

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“…In this study, we designed a putative aptamer against AQP2, which is a water channel responsible of facultative renal water reabsorption. Further investigations are further needed to exploit AQP2-nanoparticles based gene therapy to specifically rescue AQP2 physiological functions in a genetic disease whose main hallmark is impaired water reabsorption [62][63][64][65][66].…”

Section: Cytotoxicity Of Apt On Peg-aunps and Apt In Peg-aunps In Renmentioning

confidence: 99%

Aptamer Grafting onto (on) and into (in) Pegylated Gold Nanoparticles: Physicochemical Characterization and In vitro Cytotoxicity Investigation in Renal Cells

Arib¹,

Milano²,

Gerbino³

et al. 2018

J Nanomed Nanotechnol

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Gold Nanoparticles (AuNPs) have already a remarkable interest as viable biomedical materials. Additionally, the strategy of using biomolecules to modify their surface properties is a very attractive as it leads to the generation of new nanometric hybrid materials. In this respect, aptamers, functional small single-strand oligonucleotides (DNA or RNA), are ideal candidates for molecular targeting applications since the high affinity to their target molecules. Thus, the urge of new and effective methodologies to graft aptamers on AuNPs is rapidly increasing especially for applications in bioanalysis and biomedicine, including early diagnosis and drug delivery. Here we used two chemical methodologies to conjugate the aptamer (APT) onto pegylated gold nanoparticles (PEG-AuNPs): the carbodiimide chemistry (EDC/NHS) (methodology ON) and the chelation-bond (R-Au bond) (methodology IN). The aptamer's conjugations with the PEG-AuNPs were characterized by UV-Vis absorption, Raman Spectroscopy and transmission electron microscopy (TEM). In addition, the potential nanotoxicity of the two aptamer-conjugated AuNPs was evaluated on two different renal cell lines, being the kidneys one of the most important site of bioaccumulation upon systemic circulation. Interestingly, the two aptamer-conjugated AuNPs showed different cytotoxicity when exposed to human embryonic kidney (HEK293) and mouse collecting duct cells (M-1), indicating that cell viability has to be taken into account when choosing the proper strategy for NPs production. In conclusion this study provides two effective methods to graft aptamers on NPs and important insights regarding NPs conformation and the relative cell viability.The first grafting strategy consists of the conjugation of the AQP2 aptamer (APT) or on the PEG-AuNPs surface by carbodiimide Scheme 1: Schematic representation of the synthesis of a)APT ON PEG-AuNPs and b) APT IN PEG-AuNPs via carbodiimide chemistry (a) and chelation reaction (b) (Please note that drawings are not in scale and are not intended to be representative of the full samples composition).

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Rosiglitazone Promotes AQP2 Plasma Membrane Expression In Renal Cells Via a Ca2+-Dependent/cAMP-Independent Mechanism

Cited by 27 publications

References 79 publications

AQP2 Abundance is Regulated by the E3-Ligase CHIP Via HSP70

AQP2 Abundance is Regulated by the E3-Ligase CHIP Via HSP70

Metformin improves urine concentration in rodents with nephrogenic diabetes insipidus

Aptamer Grafting onto (on) and into (in) Pegylated Gold Nanoparticles: Physicochemical Characterization and In vitro Cytotoxicity Investigation in Renal Cells

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