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10. Regulation of CFTR Bicarbonate Channel Activity by WNK1: Implications for Pancreatitis and CFTR-Related DisordersSummary

Author

Yonjung Kim, Ikhyun Jun, Dong Hoon Shin, Jihoon G. Yoon, He Piao, Jinsei Jung, Hyun Woo Park, Mary Hongying Cheng, Ivet Bahar, David C. Whitcomb, and Min Goo Lee

Subjects
Diseases of the digestive system. Gastroenterology, RC799-869
Abstract

Backgraoud & Aims: Aberrant epithelial bicarbonate (HCO3−) secretion caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene is associated with several diseases including cystic fibrosis and pancreatitis. Dynamically regulated ion channel activity and anion selectivity of CFTR by kinases sensitive to intracellular chloride concentration ([Cl−]i) play an important role in epithelial HCO3− secretion. However, the molecular mechanisms of how [Cl−]i-dependent mechanisms regulate CFTR are unknown. Methods: We examined the mechanisms of the CFTR HCO3− channel regulation by [Cl−]i-sensitive kinases using an integrated electrophysiological, molecular, and computational approach including whole-cell, outside-out, and inside-out patch clamp recordings and molecular dissection of WNK1 and CFTR proteins. In addition, we analyzed the effects of pancreatitis-causing CFTR mutations on the WNK1-mediated regulation of CFTR. Results: Among the WNK1, SPAK, and OSR1 kinases that constitute a [Cl−]i-sensitive kinase cascade, the expression of WNK1 alone was sufficient to increase the CFTR bicarbonate permeability (PHCO3/PCl) and conductance (GHCO3) in patch clamp recordings. Molecular dissection of the WNK1 domains revealed that the WNK1 kinase domain is responsible for CFTR PHCO3/PCl regulation by direct association with CFTR, while the surrounding N-terminal regions mediate the [Cl−]i-sensitivity of WNK1. Furthermore, the pancreatitis-causing R74Q and R75Q mutations in the elbow helix 1 of CFTR hampered WNK1-CFTR physical associations and reduced WNK1-mediated CFTR PHCO3/PCl regulation. Conclusion: The CFTR HCO3− channel activity is regulated by [Cl−]i and a WNK1-dependent mechanism. Our results provide new insights into the regulation of the ion selectivity of CFTR and the pathogenesis of CFTR-related disorders. Keywords: Bicarbonate Secretion, Epithelia, Pancreatitis, Ion Selectivity

Published
2020
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11. Dehydrogenation of Aqueous Formic Acid by Iridium and Ruthenium Complexes with Nitrogen‐rich Diamino‐bis(1H‐1,2,4‐triazole).

Author

Ge, Shun, Liu, Jia‐Hao, Gong, Lishan, Mo, Xiu‐Fang, Liu, Chao, Yi, Xiao‐Yi, and He, Piao

Subjects
FORMIC acid, RUTHENIUM compounds, DEHYDROGENATION, IRIDIUM, KINETIC isotope effects, LITHIUM borohydride
Abstract

The development of efficient catalysts for the dehydrogenation of formic acid (FA) through molecular level control and precise regulation remains challenging. Herein, we report the newly developed complexes of iridium and ruthenium with nitrogen‐rich ligand for aqueous FA dehydrogenation. The Cp*Ir complex 1 (Cp*=cyclopentadienyl) and Ru(p‐cym) complex 2 (p‐cym=p‐Cymene) were synthesized and fully characterized. The single crystal structures of these complexes have a typical piano‐stool structure. A turnover frequency of 12468 h−1 was achieved for FA dehydrogenation at 90 °C by using complex 1 bearing 3,3'‐diamino‐5,5'‐bis(1H‐1,2,4‐triazole) (DABT). The effects of pH, temperature, concentration of formic acid and amount of catalyst on the reaction kinetics were studied in detail. Kinetic isotope effect (KIE) experiments and 1H NMR detection of reaction revealed that a plausible mechanism involves the decarboxylation of formate and the formation of H2. More importantly, the influence of H2O and H+ was involved in the rate‐determining step. This study demonstrated the effectiveness of nitrogen‐rich ligand for FA dehydrogenation, which would contribute to the development of new and effective hydrogen release systems. [ABSTRACT FROM AUTHOR]

Published
2024
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15. Homoleptic Al(III) Photosensitizers for Durable CO2 Photoreduction

Author

Wang, Jia-Wei, primary, Ma, Fan, additional, Jin, Tao, additional, He, Piao, additional, Luo, Zhi-Mei, additional, Kupfer, Stephan, additional, Karnahl, Michael, additional, Zhao, Fengyi, additional, Xu, Zihao, additional, Lian, Tianquan, additional, Huang, Yong-Liang, additional, Jiang, Long, additional, Fu, Li-Zhi, additional, Ouyang, Gangfeng, additional, and Yi, Xiao-Yi, additional

Published
2022
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22. Regulation of CFTR Bicarbonate Channel Activity by WNK1: Implications for Pancreatitis and CFTR-Related Disorders

Author

Ikhyun Jun, Min Goo Lee, Jinsei Jung, Jihoon G. Yoon, Mary Hongying Cheng, Yonjung Kim, David C. Whitcomb, He Piao, Dong Hoon Shin, Hyun Woo Park, and Ivet Bahar

Subjects
IBMX, 3-isobutyl-1-methylxanthine, 0301 basic medicine, Patch-Clamp Techniques, Cystic Fibrosis, Cystic Fibrosis Transmembrane Conductance Regulator, Po, open probability, Erev, reversal potential, Crystallography, X-Ray, Cystic fibrosis, GST, glutathione S-transferase, OSR1, oxidative stress-responsive kinase 1, 0302 clinical medicine, WNK Lysine-Deficient Protein Kinase 1, PRD, proline-rich domain, WNK1, with-no-lysine kinase 1, Bicarbonate Secretion, Original Research, GFP, green fluorescent protein, NL, N-linker, biology, Kinase, Chemistry, Gastroenterology, respiratory system, WNK1, MD, molecular dynamics, Recombinant Proteins, Cystic fibrosis transmembrane conductance regulator, I-V, current-voltage, 3. Good health, Cell biology, 030211 gastroenterology & hepatology, Epithelia, Intracellular, congenital, hereditary, and neonatal diseases and abnormalities, SDS, sodium dodecyl sulfate, Molecular Dynamics Simulation, Protein Serine-Threonine Kinases, 03 medical and health sciences, Chlorides, Protein Domains, NMDG, N-methyl-D-glucamine, medicine, Ion Selectivity, Humans, CFTR, cystic fibrosis transmembrane conductance regulator, Secretion, Patch clamp, lcsh:RC799-869, Sequence Homology, Amino Acid, Hepatology, PHCO3/PCl, HCO3-/Cl– permeability ratio, medicine.disease, NKCC, Na+-K+-Cl− cotransporter, SPAK, STE20/SPS1-related proline/alanine-rich kinase, WT, wild-type, digestive system diseases, HCO3−, bicarbonate, respiratory tract diseases, Bicarbonates, HEK293 Cells, 030104 developmental biology, Pancreatitis, Protein kinase domain, siRNA, small interfering RNA, Mutation, biology.protein, lcsh:Diseases of the digestive system. Gastroenterology, PKA, protein kinase A, STE20, sterile 20
Abstract

Backgraoud & Aims Aberrant epithelial bicarbonate (HCO3−) secretion caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene is associated with several diseases including cystic fibrosis and pancreatitis. Dynamically regulated ion channel activity and anion selectivity of CFTR by kinases sensitive to intracellular chloride concentration ([Cl−]i) play an important role in epithelial HCO3− secretion. However, the molecular mechanisms of how [Cl−]i-dependent mechanisms regulate CFTR are unknown. Methods We examined the mechanisms of the CFTR HCO3− channel regulation by [Cl−]i-sensitive kinases using an integrated electrophysiological, molecular, and computational approach including whole-cell, outside-out, and inside-out patch clamp recordings and molecular dissection of WNK1 and CFTR proteins. In addition, we analyzed the effects of pancreatitis-causing CFTR mutations on the WNK1-mediated regulation of CFTR. Results Among the WNK1, SPAK, and OSR1 kinases that constitute a [Cl−]i-sensitive kinase cascade, the expression of WNK1 alone was sufficient to increase the CFTR bicarbonate permeability (PHCO3/PCl) and conductance (GHCO3) in patch clamp recordings. Molecular dissection of the WNK1 domains revealed that the WNK1 kinase domain is responsible for CFTR PHCO3/PCl regulation by direct association with CFTR, while the surrounding N-terminal regions mediate the [Cl−]i-sensitivity of WNK1. Furthermore, the pancreatitis-causing R74Q and R75Q mutations in the elbow helix 1 of CFTR hampered WNK1-CFTR physical associations and reduced WNK1-mediated CFTR PHCO3/PCl regulation. Conclusion The CFTR HCO3− channel activity is regulated by [Cl−]i and a WNK1-dependent mechanism. Our results provide new insights into the regulation of the ion selectivity of CFTR and the pathogenesis of CFTR-related disorders., Graphical abstract

Published
2020

25. Homoleptic Al(III) Photosensitizers for Durable CO2Photoreduction

Author

Wang, Jia-Wei, Ma, Fan, Jin, Tao, He, Piao, Luo, Zhi-Mei, Kupfer, Stephan, Karnahl, Michael, Zhao, Fengyi, Xu, Zihao, Jin, Tao, Lian, Tianquan, Huang, Yong-Liang, Jiang, Long, Fu, Li-Zhi, Ouyang, Gangfeng, and Yi, Xiao-Yi

Abstract

Exploiting noble-metal-free systems for high-performance photocatalytic CO2reduction still presents a key challenge, partially due to the long-standing difficulties in developing potent and durable earth-abundant photosensitizers. Therefore, based on the very cheap aluminum metal, we have deployed a systematic series of homoleptic Al(III) photosensitizers featuring 2-pyridylpyrrolide ligands for CO2photoreduction. The combined studies of steady-state and time-resolved spectroscopy as well as quantum chemical calculations demonstrate that in anerobic CH3CN solutions at room temperature, visible-light excitation of the Al(III) photosensitizers leads to an efficient population of singlet excited states with nanosecond-scale lifetimes and notable emission quantum yields (10–40%). The results of transient absorption spectroscopy further identified the presence of emissive singlet and unexpectedly nonemissive triplet excited states. More importantly, the introduction of methyl groups at the pyrrolide rings can greatly improve the visible-light absorption, reducing power, and durability of the Al(III) photosensitizers. With triethanolamine, BIH (1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole), and an Fe(II)-quaterpyridine catalyst, the most methylated Al(III) photosensitizer achieves an apparent quantum efficiency of 2.8% at 450 nm for selective (>99%) CO2-to-CO conversion, which is nearly 28 times that of the unmethylated one (0.1%) under identical conditions. The optimal system realizes a maximum turnover number of 10250 and higher robustness than the systems with Ru(II) and Cu(I) benchmark photosensitizers. Quenching experiments using fluorescence spectroscopy elucidate that the photoinduced electron transfer in the Al(III)-sensitized system follows a reductive quenching pathway. The remarkable tunability and cost efficiency of these Al(III) photosensitizers should allow them as promising components in noble-metal-free systems for solar fuel conversion.

Published
2023
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31. ANO9/TMEM16J promotes tumourigenesis via EGFR and is a novel therapeutic target for pancreatic cancer

Author

He Piao, Hei Cheul Jeung, Byeong Gyu Yun, Yong Hoon Cha, Hyung Soon Park, Ikhyun Jun, Joon Seong Park, Jinsei Jung, You Keun Shin, Min Ji An, Xianglan Zhang, Dong Sup Yoon, Jung Woo Han, Min Goo Lee, Jong In Yook, and Heon Yung Gee

Subjects
Male, 0301 basic medicine, Oncology, Cancer Research, Carcinogenesis, pancreatic cancer, medicine.disease_cause, Deoxycytidine, ANO9/TMEM16J, Mice, Phospholipid Transfer Proteins, prognostic factor, Tumor Stem Cell Assay, Aged, 80 and over, Middle Aged, Prognosis, Anti-Bacterial Agents, ErbB Receptors, Survival Rate, Doxycycline, Gene Knockdown Techniques, Female, Carcinoma, Pancreatic Ductal, Adult, Disease free survival, medicine.medical_specialty, EGFR, Anoctamins, Antineoplastic Agents, Disease-Free Survival, target, Erlotinib Hydrochloride, 03 medical and health sciences, Cell Line, Tumor, Internal medicine, Pancreatic cancer, Biomarkers, Tumor, Carcinoma, medicine, Animals, Humans, RNA, Messenger, Aged, Cell Proliferation, business.industry, HEK 293 cells, Membrane Proteins, medicine.disease, Gemcitabine, Pancreatic Neoplasms, HEK293 Cells, 030104 developmental biology, Translational Therapeutics, business, Neoplasm Transplantation
Abstract

Background: Anoctamin (ANO)/transmembrane member 16 (TMEM16) proteins mediate diverse physiological and pathophysiological functions including cancer cell proliferation. The present study aimed to identify the role of ANOs in pancreatic cancer. Methods: In an initial screen of ANOs, ANO9/TMEM16J was overexpressed in pancreatic cancer cells, and its role in the pathogenesis of pancreatic cancer was evaluated using an integrated in vitro and in vivo approach. To determine clinical relevance of the experimental findings, the prognostic value of ANO9 was evaluated in patients with pancreatic cancer. Results: The ANO9 mRNA and protein levels were increased in pancreatic cancer-derived cells. Exogenous expression of ANO9 in PANC-1 cells significantly increased cell proliferation in cell cultures and in mice. In contrast, knockdown of ANO9 in AsPC-1, BxPC-3, and Capan-2 cells strongly inhibited cell proliferation. Mechanistic analysis suggested that physical association of ANO9 with epidermal growth factor receptor (EGFR) underlies ANO9-induced cell proliferation. Knockdown of ANO9 augmented the effects of the EGFR inhibitor and the cytotoxic agent on pancreatic cancer cell proliferation. In addition, high ANO9 expression is a poor prognostic factor in patients with pancreatic cancer. Conclusions: The ANO9/TMEM16J appears to be a clinically useful prognostic marker for pancreatic cancer and a potential therapeutic target.

Published
2017

34. Furan-containing double tetraoxa[7]helicene and its radical cation

Author

Chang, Hao, primary, Liu, Haoliang, additional, Dmitrieva, Evgenia, additional, Chen, Qiang, additional, Ma, Ji, additional, He, Piao, additional, Liu, Pengcai, additional, Popov, Alexey A., additional, Cao, Xiao-Yu, additional, Wang, Xiao-Ye, additional, Zou, Yingping, additional, Narita, Akimitsu, additional, Müllen, Klaus, additional, Peng, Hongjian, additional, and Hu, Yunbin, additional

Published
2020
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41. Monomerization and ER Relocalization of GRASP Is a Requisite for Unconventional Secretion of CFTR

Author

Hyun Soo Cho, Min Goo Lee, Dong Hee Kim, Jeong Seok Cha, He Piao, Woo Young Chung, Kuglae Kim, Jiyoon Kim, Joo Young Kim, and Shin Hye Noh

Subjects
0301 basic medicine, Endoplasmic reticulum, Mutant, Regulator, Cell Biology, Golgi reassembly, Biology, Biochemistry, Transmembrane protein, Cell biology, 03 medical and health sciences, 030104 developmental biology, Structural Biology, Genetics, Unfolded protein response, Phosphorylation, Secretion, Molecular Biology
Abstract

Induction of endoplasmic reticulum (ER)-to-Golgi blockade or ER stress induces Golgi reassembly stacking protein (GRASP)-mediated, Golgi-independent unconventional cell-surface trafficking of the folding-deficient ΔF508-cystic fibrosis transmembrane conductance regulator (CFTR). However, molecular mechanisms underlying this process remain elusive. Here, we show that phosphorylation-dependent dissociation of GRASP homotypic complexes and subsequent relocalization of GRASP to the ER play a critical role in the unconventional secretion of CFTR. Immunolocalization analyses of mammalian cells revealed that the Golgi protein GRASP55 was redistributed to the ER by stimuli that induce unconventional secretion of ΔF508-CFTR, such as induction of ER-to-Golgi blockade by the Arf1 mutant. Notably, the same stimuli also induced phosphorylation of regions near the C-terminus of GRASP55 and dissociation of GRASP homomultimer complexes. Furthermore, phosphorylation-mimicking mutations of GRASP55 induced the monomerization and ER relocalization of GRASP55, and these changes were nullified by phosphorylation-inhibiting mutations. These results provide mechanistic insights into how GRASP accesses the ER-retained ΔF508-CFTR and mediates the ER stress-induced unconventional secretion pathway.

Published
2016

49. Metal–Ligand Cooperation in Cp*Ir-Pyridylpyrrole Complexes: Rational Design and Catalytic Activity in Formic Acid Dehydrogenation and CO2Hydrogenation under Ambient Conditions

Author

Mo, Xiu-Fang, Liu, Chao, Chen, Ze-Wen, Ma, Fan, He, Piao, and Yi, Xiao-Yi

Abstract

Interconversion between CO2+ H2and FA/formate is the most promising strategy for the fixation of carbon dioxide and reversible hydrogen storage; however, FA dehydrogenation and CO2hydrogenation are usually studied separately using different catalysts for each reaction. This report describes of the catalysis of [Cp*Ir(N∧N)(X)]n+(Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl; X = Cl, n= 0; X = H2O, n= 1) bearing a proton-responsive N∧N pyridylpyrrole ligand for both reactions. Complex 2-H2Ocatalyzes FA dehydrogenation at 90 °C with a TOFmaxof 45 900 h–1. Its catalysis is more active in aqueous solution than in neat solution under base-free conditions. These complexes also catalyze CO2hydrogenation in the presence of base to formate under atmospheric pressure (CO2/H2= 0.05 MPa/0.05 MPa) at 25 °C with a TOF value of 4.5 h–1in aqueous solution and with a TOF value of 29 h–1in a methanol/H2O mixture solvent. The possible mechanism is proposed by intermediate characterization and KIE experiments. The extraordinary activity of these complexes are mainly attributed to the metal–ligand cooperative effect of the the pyrrole group to accept a proton in the dehydrogenation of formic acid and assist cooperative heterolytic H–H bond cleavage in CO2hydrogenation.

Published
2021
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50. Design of New Bridge-Ring Energetic Compounds Obtained by Diels–Alder Reactions of Tetranitroethylene Dienophile

Author

He, Piao, Mei, Hao-Zheng, Wu, Le, Yang, Jun-Qing, Zhang, Jian-Guo, Cohen, Adva, and Gozin, Michael

Abstract

The density functional theory method was employed to calculate three-dimensional structures for a series of novel explosophores. The design of new molecules (DA1–DA12) was based on the bridge-ring structures that could be formed via Diels–Alder (DA) reaction of selected nitrogen-rich dienes and tetranitroethylene dienophile. The feasibility of the proposed DA reactions was predicted on the basis of the molecular orbital theory. The strong interactions between the HOMO of dienes, with electron-donating groups (Diene2, Diene6, and Diene8), and the LUMO of tetranitroethylene dienophile suggested thermodynamically favorable formation of the desired DA reaction products. In addition to molecular structures of the explored DA compounds, their physicochemical and energetic properties were also calculated in detail. Due to compact bridge-ring structures, new energetic molecules have highly positive heats of formation (up to 1124.90 kJ·mol–1) and high densities (up to 2.04 g·cm–3). Also, as a result of all-right ratios of nitrogen and oxygen, most of the new compounds possess high detonation velocities (8.28–10.02 km·s–1) and high detonation pressures (30.87–47.83 GPa). Energetic compounds DA1, DA4, and DA12exhibit a superior detonation performance over widely used HMX explosive, and DA5, DA7, and DA10could be comparable to the state-of-the-art CL-20 and ONC explosives. Our proposed designs and synthetic methodology should provide a platform for the development of novel energetic materials with superior performance.

Published
2024
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