A5040397891- Ion Transport and Channel Regulation
- Electrolyte and hormonal disorders
- Neuroendocrine regulation and behavior
- Receptor Mechanisms and Signaling
- Ion channel regulation and function
- Renal and related cancers
- Hormonal Regulation and Hypertension
- Pancreatic function and diabetes
- Neonatal Respiratory Health Research
- Renin-Angiotensin System Studies
- Circadian rhythm and melatonin
- Chemical Synthesis and Analysis
- Monoclonal and Polyclonal Antibodies Research
- Cellular transport and secretion
- Erythrocyte Function and Pathophysiology
- Renal function and acid-base balance
- Caveolin-1 and cellular processes
- Protein Kinase Regulation and GTPase Signaling
- Genetic and Kidney Cyst Diseases
- Cell death mechanisms and regulation
- Lung Cancer Treatments and Mutations
- ATP Synthase and ATPases Research
- Birth, Development, and Health
- Coagulation, Bradykinin, Polyphosphates, and Angioedema
- RNA Interference and Gene Delivery
Harvard University
2015-2025
Massachusetts General Hospital
2015-2025
MGH Institute of Health Professions
2017-2024
Center for Systems Biology
2010-2019
Laboratoire de Biologie Physico-Chimique des Protéines Membranaires
2013
Université de Sherbrooke
1994-2011
Harvard University Press
2009
Deficiencies in DNA-degrading nucleases lead to accumulation of self DNA and induction autoimmunity mice monogenic polygenic human diseases. However, the sources mechanisms that trigger immunity remain unclear. We analyzed deficient for lysosomal nuclease Dnase2a observed elevated levels undegraded both phagocytic nonphagocytic cells. In cells, excess originated from damaged nucleus based on colocalization studies, live-cell imaging, exacerbation by DNA-damaging agents. Removal required...
In collecting duct principal cells, aquaporin 2 (AQP2) is shuttled from intracellular vesicles to the plasma membrane upon vasopressin (VP) stimulation. VP activates adenylyl cyclase, increases cAMP, activating protein kinase A (PKA) phosphorylate AQP2 on COOH-terminal residue, serine 256. Using rat kidney slices and LLC-PK1 cells stably expressing (LLC-AQP2 cells), we now show that trafficking can be stimulated by cAMP-independent pathways. these systems, nitric oxide (NO) donors sodium...
Aquaporin-4 (AQP4) water channels exist as heterotetramers of M1 and M23 splice variants appear to be present in orthogonal arrays intramembraneous particles (OAPs) visualized by freeze-fracture microscopy. We report that AQP4 forms OAPs rat gastric parietal cells but not from the mouse or kangaroo rat. Furthermore, organization principal cell Brattleboro kidney is perturbed vasopressin (arginine vasopressin). Membranes LLC-PK(1) expressing M23-AQP4 showed large, abundant OAPs, none were...
Inhibition of clathrin-mediated endocytosis by expression a GTPase-deficient dynamin mutant (dynamin-2/K44A) for 16 h results in an accumulation plasma membrane aquaporin-2 (AQP2) epithelial cells stably transfected with wild-type AQP2. We now show similar effect K44A LLC-PK 1 S256 phosphorylation-deficient AQP2 mutant, AQP2(S256A), and AQP2-transfected inner medullary collecting duct (IMCD) cells. More acute blockade these the cholesterol-depleting agent methyl-β-cyclodextrin (mβCD; 10 mM)...
Vasopressin-stimulated insertion of the aquaporin 2 (AQP2) water channel into plasma membrane kidney collecting duct principal cells is a key event in urinary concentrating mechanism. The paradigm for vasopressin-receptor signaling involves cAMP-mediated protein kinase A activation, which results functionally critical phosphorylation AQP2 on amino acid serine 256. We previously showed that parallel cGMP-mediated pathway also leads to AQP2-transfected LLC-PK1 (LLC-AQP2) and outer medullary...
The trafficking of aquaporin-2 (AQP2) involves multiple complex pathways, including regulated, cAMP-, and cGMP-mediated as well a constitutive recycling pathway. Although several accessory proteins have been indirectly implicated in AQP2 recycling, the direct protein-protein interactions that regulate this process remain largely unknown. Using yeast two-hybrid screening human kidney cDNA library, we identified 70-kDa heat shock AQP2-interacting proteins. Interaction was confirmed by mass...
Phosphorylation of serine 256 (S256) plays a critical role in vasopressin (VP)-mediated membrane accumulation aquaporin-2 (AQP2). Recently, phosphorylation 261 was also reported, raising the possibility that it has AQP2 trafficking. We addressed this issue using transfected LLC-PK(1) cells express point mutations S261 and S256, mimicking phosphorylated (S to D) or dephosphorylated A) states these residues. Both (S261A) (S261D) were located perinuclear cytoplasm without stimulation but, like...
Statins are 3-hydroxyl-3-methyglutaryl-CoA reductase inhibitors that commonly used to inhibit cholesterol biosynthesis. Emerging data have suggested they also "pleotropic effects," including modulating actin cytoskeleton reorganization. Here, we report an effect of simvastatin on the trafficking aquaporin-2 (AQP2). Specifically, induced membrane accumulation AQP2 in cell cultures and kidneys situ. The was independent protein kinase A activation phosphorylation at AQP2-Ser(256), a critical...
Uncontrolled inflammation is one of the leading causes kidney failure. Pro-inflammatory responses can occur in absence infection, a process called sterile inflammation. Here we show that purinergic receptor P2Y14 (GPR105) specifically and highly expressed collecting duct intercalated cells (ICs) mediates kidney. activated by UDP-glucose, damage-associated molecular pattern molecule (DAMP) released injured cells. We found UDP-glucose increases pro-inflammatory chemokine expression ICs as well...
Before the identification of aquaporin (AQP) proteins, vasopressin-regulated "water channels" were identified by freeze-fracture electron microscopy as aggregates or clusters intramembraneous particles (IMPs) on hormonally stimulated target cell membranes. In kidney collecting duct, these IMP subsequently possible sites clathrin-coated pit formation plasma membrane, and a clathrin-mediated mechanism for internalization vasopressin-sensitive water channels was suggested. Using an antibody...
Osmotic homeostasis is fundamental for most cells, which face recurrent alterations of environmental osmolality that challenge cell viability. Protein damage a consequence hypertonic stress, but whether autophagy contributes to the osmoprotective response unknown. Here, we investigated possible implications and microtubule organization on stress. We show hypertonicity rapidly induced long-lived protein degradation, LC3-II generation Ptdlns3K-dependent formation LC3- ATG12-positive puncta....
Nephrogenic diabetes insipidus (NDI) is caused by impairment of vasopressin (VP) receptor type 2 signaling. Because potential therapies for NDI that target the canonical VP/cAMP/protein kinase A pathway have so far proven ineffective, alternative strategies modulating aquaporin (AQP2) trafficking been sought. Successful identification compounds our high–throughput chemical screening assay prompted us to determine whether EGF (EGFR) inhibitors stimulate AQP2 and reduce urine output....
Renal tubulo-interstitial inflammation is frequently associated with polyuria and urine concentration defects. This led us to investigate the effects of major pro-inflammatory nuclear factor κB (NF-κB) pathway on aquaporin 2 (AQP2) expression by collecting duct. Using immortalized duct principal cells (mpkCCDcl4), we found that, acting independently vasopressin, activation NF-κBby lipopolysaccharide (LPS) decreased AQP2 mRNA protein levels in a time- dose-dependent manner but did not...
The most common cause of hereditary nephrogenic diabetes insipidus is a nonfunctional vasopressin (VP) receptor type 2 (V2R). Calcitonin, another ligand G-protein–coupled receptors, has VP-like effect on electrolytes and water reabsorption, suggesting that it may affect AQP2 trafficking. Here, calcitonin increased intracellular cAMP stimulated the membrane accumulation in LLC-PK1 cells. Pharmacologic inhibition protein kinase A (PKA) deficiency critical PKA phosphorylation site both...