Project description:Primary aldosteronism (PA), a common cause of severe hypertension, features constitutive production of the adrenal steroid aldosterone. We analyzed a multiplex family with familial hyperaldosteronism type II (FH-II) and 80 additional probands with unsolved early-onset PA. Eight probands had novel heterozygous variants in CLCN2, including two de novo mutations and four independent occurrences of the identical p.Arg172Gln mutation; all relatives with early-onset PA carried the CLCN2 variant found in probands. CLCN2 encodes a voltage-gated chloride channel expressed in adrenal glomerulosa that opens at hyperpolarized membrane potentials. In this data set, we examined RNA expression in H295R cells transfected with empty vector, WT and p.Arg172Gln CLCN2. Expression of CLCN2 led to increased expression of CYP11B2 and its upstream regulator NR4A2.
Project description:Taste substances are received by taste receptors expressed in taste cells. “Salty taste” sensation is evoked when sodium and chloride ions are present together in the oral cavity. The presence of an epithelial cation channel that receives Na+ has previously been reported. However, no molecular entity involving Cl- receptors has been elucidated. We report the strong expression of transmembrane channel-like 4 (TMC4) in the circumvallate and foliate papillae projected to the glossopharyngeal nerve, mediating a high-concentration of NaCl. Electrophysiological analysis using HEK293T cells revealed that TMC4 was a voltage-dependent Cl- channel and the consequent currents were completely inhibited by NPPB, an anion channel blocker. This channel could be activated without an increase in intracellular calcium ion. TMC4 allowed permeation of organic anions including gluconate, but their current amplitudes at positive potentials were less than that of Cl-. Tmc4-deficient mice showed significantly weaker glossopharyngeal nerve response to high-concentration of NaCl than the wild-type littermates. These results indicated that TMC4 is a novel chloride channel that responds to high-concentration of NaCl.
Project description:Methylene diphenyl diisocyanate is a chemical known to cause asthma. The present study uses mice to investigate exposure-induced changes in lung gene expression and effects of a chloride channel inhibitor We used microarrays to detail global whole lung gene expression following respiratory tract exposure to methylene diphenyl diisocyanate (MDI) vs. control exposure in mice immune-sensitized to MDI by prior skin exposure. In some studies mice were given a chloride channel inhibitor (crofelemer) via the respiratory tract before MDI.
Project description:Transcriptomic profiling of Pseudomonas fluorescens Pf-5 comparing iron(II) chloride supplemented grown culture against non-iron treated grown culture in M9 minimal media Two-condition experiment, iron(II) chloride supplemented culture versus non-iron treated culture. 4 biological replicates including 3 technical replicates for one of the biological replicates. Swap-dye experiments were performed
Project description:Regulation of cell volume is essential for tissue homeostasis and cell viability. In response to hypertonic stress, cells need rapid electrolyte influx to compensate water loss and to prevent cell death in a process known as regulatory volume increase (RVI). However, the molecular component able to trigger such process was unknown to date. Using a genome wide CRISPR/Cas9 screen, we identified LRRC8A, which encodes a chloride channel subunit, as the gene most associated with cell survival under hypertonic conditions. Hypertonicity activates the p38 stress-activated protein kinase pathway and its downstream MSK1 kinase, which phosphorylates and activates LRRC8A. LRRC8A-mediated Cl efflux facilitates activation of the with-no-lysine (WNK) kinase pathway, which in turn, promotes electrolyte influx via Na+ /K+ /2Cl cotransporter (NKCC) and RVI under hypertonic stress. LRRC8A-S217A mutation impairs channel activation by MSK1, resulting in reduced RVI and cell survival. In summary, LRRC8A is key to bidirectional osmotic stress responses and cell survival under hypertonic conditions.
Project description:Osteoclast over-activation leads to bone loss and chloride homeostasis is fundamental for osteoclast function. The calcium-activated chloride channel Anoctamin 1 (also known as TMEM16A) is an important chloride channel involved in many physiological processes. However, its role in osteoclasts remains unresolved. Here, we identify the existence of Anoctamin 1 in osteoclasts and show that its expression positively correlates with osteoclast activity. Osteoclast-specific Anoctamin 1 knockout mice exhibit increased bone mass and decreased bone resorption. Mechanistically, Anoctamin 1 deletion increases intracellular Cl- concentration, decreases H+ secretion and reduces bone resorption. Notably, Anoctamin 1 physically interacts with RANK and this interaction is dependent upon Anoctamin 1 channel activity, jointly promoting RANKL-induced downstream signaling pathways. Anoctamin 1 protein levels are substantially increased in osteoporosis patients and this closely correlates with osteoclast activity. Finally, Anoctamin 1 deletion significantly alleviates ovariectomy induced osteoporosis. These results collectively establish Anoctamin 1 as an essential regulator in osteoclast function and suggest a potential therapeutic target for osteoporosis.
Project description:Analysis of leaves of wild-type and jasmonate (JA)-deficeint mutant cpm2 treated with CuCl2. Results provide the role of JA on defence responses after copper chloride treatment.