112 results on '"Jianghui Hou"'
Search Results
2. Encephalitic Alphaviruses Exploit Caveola-Mediated Transcytosis at the Blood-Brain Barrier for Central Nervous System Entry
- Author
-
Hamid Salimi, Matthew D. Cain, Xiaoping Jiang, Robyn A. Roth, Wandy L. Beatty, Chengqun Sun, William B. Klimstra, Jianghui Hou, and Robyn S. Klein
- Subjects
IFNAR ,Venezuelan encephalitis virus ,western equine encephalitis virus ,alphavirus ,blood-brain barrier ,caveola-mediated transcytosis ,Microbiology ,QR1-502 - Abstract
ABSTRACT Venezuelan and western equine encephalitis viruses (VEEV and WEEV, respectively) invade the central nervous system (CNS) early during infection, via neuronal and hematogenous routes. While viral replication mediates host shutoff, including expression of type I interferons (IFN), few studies have addressed how alphaviruses gain access to the CNS during established infection or the mechanisms of viral crossing at the blood-brain barrier (BBB). Here, we show that hematogenous dissemination of VEEV and WEEV into the CNS occurs via caveolin-1 (Cav-1)-mediated transcytosis (Cav-MT) across an intact BBB, which is impeded by IFN and inhibitors of RhoA GTPase. Use of reporter and nonreplicative strains also demonstrates that IFN signaling mediates viral restriction within cells comprising the neurovascular unit (NVU), differentially rendering brain endothelial cells, pericytes, and astrocytes permissive to viral replication. Transmission and immunoelectron microscopy revealed early events in virus internalization and Cav-1 association within brain endothelial cells. Cav-1-deficient mice exhibit diminished CNS VEEV and WEEV titers during early infection, whereas viral burdens in peripheral tissues remained unchanged. Our findings show that alphaviruses exploit Cav-MT to enter the CNS and that IFN differentially restricts this process at the BBB. IMPORTANCE VEEV, WEEV, and eastern equine encephalitis virus (EEEV) are emerging infectious diseases in the Americas, and they have caused several major outbreaks in the human and horse population during the past few decades. Shortly after infection, these viruses can infect the CNS, resulting in severe long-term neurological deficits or death. Neuroinvasion has been associated with virus entry into the CNS directly from the bloodstream; however, the underlying molecular mechanisms have remained largely unknown. Here, we demonstrate that following peripheral infection alphavirus augments vesicular formation/trafficking at the BBB and utilizes Cav-MT to cross an intact BBB, a process regulated by activators of Rho GTPases within brain endothelium. In vivo examination of early viral entry in Cav-1-deficient mice revealed significantly lower viral burdens in the brain than in similarly infected wild-type animals. These studies identify a potentially targetable pathway to limit neuroinvasion by alphaviruses.
- Published
- 2020
- Full Text
- View/download PDF
3. MicroRNA Regulation in Renal Pathophysiology
- Author
-
Jianghui Hou and Dan Zhao
- Subjects
microRNA ,kidney ,diabetic nephropathy ,hypercalciuria ,hypertension ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
MicroRNAs are small, noncoding RNA molecules that regulate a considerable amount of human genes on the post-transcriptional level, and participate in many key biological processes. MicroRNA deregulation has been found associated with major kidney diseases. Here, we summarize current knowledge on the role of microRNAs in renal glomerular and tubular pathologies, with emphasis on the mesangial cell and podocyte dysfunction in diabetic nephropathy, the proximal tubular cell survival in acute kidney injury, the transport function of the thick ascending limb in Ca++ imbalance diseases, and the regulation of salt, K+ and blood pressure in the distal tubules. Identification of microRNAs and their target genes provides novel therapeutic candidates for treating these diseases. Manipulation of microRNA function with its sense or antisense oligonucleotide enables coordinated regulation of the entire downstream gene network, which has effectively ameliorated several renal disease phenotypes. The therapeutic potentials of microRNA based treatments, though promising, are confounded by major safety issues related to its target specificity, which remain to be fully elucidated.
- Published
- 2013
- Full Text
- View/download PDF
4. Insulin receptor substrate 4 deficiency mediates the insulin effect on the epithelial magnesium channel TRPM6 and causes hypomagnesemia
- Author
-
Jing Zhang, Sung Wan An, Sudha Neelam, Anuja Bhatta, Mingzhu Nie, Claudia Duran, Manjot Bal, Femke Latta, Jianghui Hou, Joseph J. Otto, Julia Kozlitina, Andrew Lemoff, Joost Hoenderop, Michel Baum, and Matthias T Wolf
- Abstract
The kidney is the key regulator of magnesium (Mg2+) homeostasis in the human body. In the distal convoluted tubule (DCT), the apical epithelial magnesium (Mg2+) channel TRPM6, determines how much Mg2+ is excreted in the urine. To better understand the regulation of human renal Mg2+ absorption we identified novel, potential interaction partners of TRPM6 by pursuing a liquid chromatography – tandem mass spectrometry (LC-MS/MS) proteomics approach.We found insulin receptor substrate 4 (IRS4) enriched with TRPM6 tagged to glutathione S-transferase (TRPM6-GST) but not GST control. Physical interaction between IRS4 and TRPM6 was confirmed by co-immunoprecipitation. Applying microdissection of mouse tubules, we detected Irs4 mRNA expression mostly in the DCT and to a lower degree in the proximal tubule and thick ascending limb of Henle. Given the overall low abundance of Irs4 mRNA along the tubule we investigated the phenotype of Irs4 knockout mice (Irs4-/-). These Irs4-/- mice displayed significantly higher urinary and fecal Mg2+ losses and lower blood Mg2+ levels than wild-type (WT) mice. Claudin-16, claudin-19, and Hnf1b mRNA and Claudin-16 and Trpm6 protein expression was significantly higher in kidneys of 3 month old Irs4-/- mice consistent with a compensatory mechanism to conserve Mg2+. Applying whole-cell patch-clamp recording we confirmed the stimulatory role of insulin on TRPM6 channel activity and showed that IRS4 targets the two TRPM6 phosphorylation sites T1391 and S1583 to enhance TRPM6 current density. To test the effect of Mg2+ deficiency on metabolism, we performed glucose and insulin tolerance studies, which were mildly abnormal in Irs4-/- mice.SIGNIFICANCE STATEMENTMagnesium (Mg2+) is the second most abundant intracellular cation but the regulation of Mg2+ homeostasis is not well understood. The kidney is the key organ for regulating Mg2+ homeostasis. Insulin is a known stimulator of the apical epithelial Mg2+channel TRPM6. We present a novel modifier of Mg2+ absorption with insulin receptor substrate 4 (IRS4) which illuminates further, how insulin activates the TRPM6 channel and modifies Mg2+ homeostasis. Applying protein biochemistry, tubular microdissection, whole mouse physiology, and patch-clamp recording, we demonstrate that IRS4 mediates the stimulatory effect of insulin by enhancing phosphorylation of two specific TRPM6 residues. Irs4-/- mice develop increased urinary and stool Mg2+ losses, lower serum Mg2+ concentration, and display mild impairment in glucose and insulin tolerance.
- Published
- 2022
5. Imaging effects of hyperosmolality on individual tricellular junctions
- Author
-
Jianghui Hou, Kaixiang Huang, Lane A. Baker, Lushan Zhou, and Kristen Alanis
- Subjects
0303 health sciences ,Tight junction ,Endothelium ,Osmotic shock ,Chemistry ,Conductance ,General Chemistry ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Canine kidney ,Renal physiology ,Osmotherapy ,medicine ,Biophysics ,Receptor ,030217 neurology & neurosurgery ,030304 developmental biology - Abstract
A nanoscale electrochemical imaging method was used to reveal heterogeneity present in conductance at epithelial cell junctions under hyperosmotic stress., The use of hyperosmolar agents (osmotherapy) has been a major treatment for intracranial hypertension, which occurs frequently in brain diseases or trauma. However, side-effects of osmotherapy on the brain, especially on the blood–brain barrier (BBB) are still not fully understood. Hyperosmolar conditions, termed hyperosmolality here, are known to transiently disrupt the tight junctions (TJs) at the endothelium of the BBB resulting in loss of BBB function. Present techniques for evaluation of BBB transport typically reveal aggregated responses from the entirety of BBB transport components, with little or no opportunity to evaluate heterogeneity present in the system. In this study, we utilized potentiometric-scanning ion conductance microscopy (P-SICM) to acquire nanometer-scale conductance maps of Madin–Darby Canine Kidney strain II (MDCKII) cells under hyperosmolality, from which two types of TJs, bicellular tight junctions (bTJs) and tricellular tight junctions (tTJs), can be visualized and differentiated. We discovered that hyperosmolality leads to increased conductance at tTJs without significant alteration in conductance at bTJs. To quantify this effect, an automated computer vision algorithm was designed to extract and calculate conductance components at both tTJs and bTJs. Additionally, lowering Ca2+ concentration in the bath facilitates tTJ disruption under hyperosmolality. Strengthening tTJ structure by overexpressing immunoglobulin-like domain-containing receptor 1 (ILDR1) protein abrogates the effect of hyperosmolality. We posit that osmotic stress physically disrupts tTJ structure, as evidenced by super-resolution microscopy. Findings from this study not only provide a high-resolution view of TJ structure and function, but also can inform current osmotherapy and drug delivery strategies for brain diseases.
- Published
- 2020
6. MP08-13 MICRORNA-29a REGULATES TGF-β1-INDUCED EXPRESSION OF COLLAGEN 1a1 IN HUMAN UROTHELIAL CELLS
- Author
-
Dale E. Bjorling, Jianghui Hou, and Zun-Yi Wang
- Subjects
business.industry ,Urology ,Cancer research ,Medicine ,Microrna 29a ,business ,Transforming growth factor - Published
- 2021
7. MP28-16 TGF-β1 REGULATES EXPRESSION OF COLLAGEN 1A1 IN MOUSE UROTHELIAL CELLS
- Author
-
Jianghui Hou, Dale E. Bjorling, and Zun-Yi Wang
- Subjects
business.industry ,Urology ,Cancer research ,Medicine ,business ,Transforming growth factor - Published
- 2020
8. Phosphorylated claudin-16 interacts with Trpv5 and regulates transcellular calcium transport in the kidney
- Author
-
Aparna Renigunta, Nina Himmerkus, Markus Bleich, Mingzhu Nie, Jianghui Hou, Matthias T.F. Wolf, Abby Sunq, Vijay Renigunta, and Catarina Quintanova
- Subjects
0301 basic medicine ,Genetically modified mouse ,Male ,Cell Membrane Permeability ,TRPV5 ,endocrine system diseases ,TRPV Cation Channels ,urologic and male genital diseases ,digestive system ,Tight Junctions ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Mutant protein ,medicine ,Animals ,Humans ,Distal convoluted tubule ,Transcellular ,Phosphorylation ,Kidney Tubules, Distal ,Mice, Knockout ,Multidisciplinary ,Chemistry ,urogenital system ,Apical membrane ,Cell biology ,030104 developmental biology ,medicine.anatomical_structure ,HEK293 Cells ,PNAS Plus ,030220 oncology & carcinogenesis ,Paracellular transport ,Claudins ,Calcium ,Calcium Channels ,Transcytosis ,tissues - Abstract
Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) was previously considered to be a paracellular channelopathy caused by mutations in the claudin-16 and claudin-19 genes. Here, we provide evidence that a missense FHHNC mutation c.908C>G (p.T303R) in the claudin-16 gene interferes with the phosphorylation in the claudin-16 protein. The claudin-16 protein carrying phosphorylation at residue T303 is localized in the distal convoluted tubule (DCT) but not in the thick ascending limb (TAL) of the mouse kidney. The phosphomimetic claudin-16 protein carrying the T303E mutation but not the wildtype claudin-16 or the T303R mutant protein increases the Trpv5 channel conductance and membrane abundance in human kidney cells. Phosphorylated claudin-16 and Trpv5 are colocalized in the luminal membrane of the mouse DCT tubule; phosphomimetic claudin-16 and Trpv5 interact in the yeast and mammalian cell membranes. Knockdown of claudin-16 gene expression in transgenic mouse kidney delocalizes Trpv5 from the luminal membrane in the DCT. Unlike wildtype claudin-16, phosphomimetic claudin-16 is delocalized from the tight junction but relocated to the apical membrane in renal epithelial cells because of diminished binding affinity to ZO-1. High-Ca(2+) diet reduces the phosphorylation of claudin-16 protein at T303 in the DCT of mouse kidney via the PTH signaling cascade. Knockout of the PTH receptor, PTH1R, from the mouse kidney abrogates the claudin-16 phosphorylation at T303. Together, these results suggest a pathogenic mechanism for FHHNC involving transcellular Ca(2+) pathway in the DCT and identify a molecular component in renal Ca(2+) homeostasis under direct regulation of PTH.
- Published
- 2020
9. Biochemical approaches for tight junction
- Author
-
Jianghui Hou
- Subjects
Ussing chamber ,Tight junction ,Chemistry ,Permeability (electromagnetism) ,Paracellular transport ,Ohmmeter ,Biophysics ,Permeation ,Flux (metabolism) ,Transepithelial potential difference - Abstract
Tight junction creates a paracellular pathway allowing ion and solute permeation on the basis of size and charge. Studies of tight junction permeability involve measurements of flux rates of ions, solutes, and water, and of transepithelial resistance and transepithelial potential. This chapter describes the key approaches used to measure tight junction permeabilities in a variety of cell and tissue models, which include, electrophysiological recording of cell cultures, epithelial tissues, epithelial ohmmeter measurement, impedance recording, flux assays, and measurement of water permeability in Ussing chamber.
- Published
- 2020
10. Electron microscopy for tight junction
- Author
-
Jianghui Hou
- Subjects
Immunolabeling ,Materials science ,Tissue sections ,Tight junction ,Transmission electron microscopy ,law ,Biophysics ,Electron microscope ,Electron microscopic ,law.invention ,Structure and function - Abstract
Tight junction was first described as membrane fusion near the apex of epithelial and endothelial cells by using electron microscopic techniques. Electron microscopy has contributed immensely to the elucidation of tight junction structure and function in cells and tissues. This chapter describes the key approaches used to visualize tight junction by electron microscopy, which include transmission electron microscopy for cell culture, transmission electron microscopy for tissue section, transmission electron microscopy for tracer assay, transmission electron microscopy for immunolabeling application, freeze-fracture electron microscopy, and freeze-fracture replica immunolabeling technique.
- Published
- 2020
11. Introduction
- Author
-
Jianghui Hou
- Published
- 2020
12. Histological approaches for tight junction
- Author
-
Jianghui Hou
- Subjects
Physics ,Tight junction ,Biophysics ,Electron microscopic ,Structure and function - Abstract
Tight junction can be studied by light and electron microscopic techniques. Fixation is essential for preserving the structure and function of tight junction in cells and tissues. This section describes the key approaches used to fix the tight junction in organs. Tight junctions are found in almost every organ, either of epithelial origin or of nonepithelial origin. This section also provides a comprehensive atlas of tight junction localization in organs, which lays down a histological premise for tight junction research.
- Published
- 2020
13. Cell models of tight junction biology
- Author
-
Jianghui Hou
- Subjects
medicine.anatomical_structure ,Tight junction ,RNA interference ,Transgene ,Cell ,medicine ,Cultured cell ,Epithelium ,Cell biology - Abstract
Tight junctions are made by epithelial or endothelial cells in culture. Cultured cell models allow tight junction proteins to be added, removed, or mutated in a controllable manner. This chapter describes the key approaches used to manipulate tight junction proteins in cell cultures, which include general protocol for epithelial cell culture, calcium switch assay, retrovirus-mediated transgene expression for tight junction proteins, and retrovirus-mediated RNA interference to silence tight junction proteins.
- Published
- 2020
14. Perspective
- Author
-
Jianghui Hou
- Published
- 2020
15. Light microscopy for tight junction
- Author
-
Jianghui Hou
- Subjects
Subcellular organelle ,Materials science ,Tissue sections ,Tight junction ,Confocal microscopy ,law ,Organelle ,Microscopy ,Fluorescence microscope ,Biophysics ,law.invention - Abstract
Tight junction is a subcellular organelle located near the apical surface of epithelial or endothelial cells. Tight junction can be decorated by antibodies against the proteins that are integral part of the organelle. This section describes the key approaches used to visualize tight junction by light microscopy, which include wide-field fluorescence microscopy for unpolarized cells, wide-field fluorescence microscopy for thin tissue section, confocal microscopy for polarized cells, and confocal microscopy for thick tissue section.
- Published
- 2020
16. Encephalitic alphaviruses exploit caveolae-mediated transcytosis at the blood-brain barrier for CNS entry
- Author
-
Robyn Roth, William B. Klimstra, Jianghui Hou, Wandy L. Beatty, Robyn S. Klein, Matthew D. Cain, Chengqun Sun, Xiaoping Jiang, and Hamid Salimi
- Subjects
education.field_of_study ,biology ,Immunoelectron microscopy ,viruses ,Population ,Alphavirus ,Blood–brain barrier ,biology.organism_classification ,Virology ,Virus ,medicine.anatomical_structure ,Transcytosis ,Viral replication ,Viral entry ,medicine ,cardiovascular system ,education - Abstract
Venezuelan and Western equine encephalitis viruses (VEEV and WEEV) invade the CNS early during infection, via neuronal and hematogenous routes (1, 2). While viral replication mediates host-shut off, including expression of type I interferons (IFN) (3, 4), few studies have addressed how alphaviruses gain access to the CNS during established infection or the mechanisms of viral crossing at the blood-brain barrier (BBB). Here, we show that hematogenous dissemination of VEEV and WEEV into the CNS occurs via caveolin (Cav)-1-mediated transcytosis (Cav-MT) across an intact BBB, which is impeded by IFN and inhibitors of RhoA GTPase. Use of reporter and non-replicative strains also demonstrates that IFN signaling mediates viral restriction within cells comprising the neurovascular unit (NVU), differentially rendering brain endothelial cells, pericytes and astrocytes permissive to viral replication. Transmission and immunoelectron microscopy revealed early events in virus internalization and Cav-1-association within brain endothelial cells. Cav-1-deficient mice exhibit diminished CNS VEEV and WEEV titers during early infection, whereas viral burdens in peripheral tissues remained unchanged. Our findings show that alphaviruses exploit Cav-MT to enter the CNS, and that IFN differentially restricts this process at the BBB.ImportanceVEEV, WEEV and EEEV are emerging infectious diseases in the Americas, and they have caused several major outbreaks in the human and horse population during the past few decades. Shortly after infection, these viruses can infect the CNS, resulting in severe long-term neurological deficits or death. Neuroinvasion has been associated with virus entry into the CNS directly from the blood-stream, however the underlying molecular mechanisms have remained largely unknown. Here we demonstrate that following peripheral infection alphavirus augments vesicular formation/trafficking at the BBB and utilizes Cav-MT to cross an intact BBB, a process regulated by activators of Rho GTPAses within brain endothelium.In vivoexamination of early viral entry in Cav-1-deficient mice revealed significantly lower viral burdens than in similarly infected wild-type animals. These studies identify a potentially targetable pathway to limit neuroinvasion by alphaviruses.
- Published
- 2019
- Full Text
- View/download PDF
17. Quantitative Visualization of Nanoscale Ion Transport
- Author
-
Yongfeng Gong, Jianghui Hou, Lane A. Baker, and Lushan Zhou
- Subjects
0301 basic medicine ,Polymers ,Synthetic membrane ,Nanotechnology ,010402 general chemistry ,01 natural sciences ,Madin Darby Canine Kidney Cells ,Analytical Chemistry ,Ion ,Nanopores ,03 medical and health sciences ,Dogs ,Monolayer ,Microscopy ,Animals ,Nanoscopic scale ,Cells, Cultured ,Ion transporter ,Ion Transport ,Microscopy, Confocal ,Chemistry ,Electric Conductivity ,Conductance ,0104 chemical sciences ,030104 developmental biology ,Membrane ,Dielectric Spectroscopy ,Potentiometry - Abstract
Understanding ion transport properties at various interfaces, especially at small length scales, is critical in advancing our knowledge of membrane materials and cell biology. Recently, we described potentiometric-scanning ion conductance microscopy (P-SICM) for ion-conductance measurement in polymer membranes and epithelial cell monolayers at discrete points in a sample. Here, we combine hopping mode techniques with P-SICM to allow simultaneous nanometer-scale conductance and topography mapping. First validated with standard synthetic membranes and then demonstrated in living epithelial cell monolayers under physiological conditions, this new method allows direct visualization of heterogeneous ion transport of biological samples for the first time. These advances provide a noncontact local probe, require no labeling, and present a new tool for quantifying intrinsic transport properties of a variety of biological samples.
- Published
- 2017
18. Virus entry and replication in the brain precedes blood-brain barrier disruption during intranasal alphavirus infection
- Author
-
Jianghui Hou, Matthew D. Cain, Samantha L. Hamilton, Robyn S. Klein, James R. Heffernan, Yongfeng Gong, Hamid Salimi, Mark J. Miller, and Lihua Yang
- Subjects
0301 basic medicine ,Adaptor Protein Complex 1 ,Immunology ,Central nervous system ,CX3C Chemokine Receptor 1 ,Mice, Transgenic ,Biology ,Virus Replication ,medicine.disease_cause ,Article ,Virus ,Capillary Permeability ,Encephalitis Virus, Venezuelan Equine ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Viral entry ,Cricetinae ,medicine ,Animals ,Immunology and Allergy ,Alphavirus infection ,Claudin ,Cells, Cultured ,Cerebral Cortex ,Alphavirus Infections ,Tumor Necrosis Factor-alpha ,Brain ,Epithelial Cells ,Virus Internalization ,medicine.disease ,Virology ,Olfactory bulb ,Mice, Inbred C57BL ,Disease Models, Animal ,030104 developmental biology ,medicine.anatomical_structure ,Animals, Newborn ,Gene Expression Regulation ,nervous system ,Neurology ,Viral replication ,Blood-Brain Barrier ,Venezuelan equine encephalitis virus ,Receptors, Chemokine ,Neurology (clinical) ,030217 neurology & neurosurgery - Abstract
Viral infections of the central nervous system (CNS) are often associated with blood-brain barrier (BBB) disruption, yet the impact of virus replication and immune cell recruitment on BBB integrity are incompletely understood. Using two-photon microscopy, we demonstrate that Venezuelan equine encephalitis virus (VEEV) strain TC83-GFP, a GFP expressing, attenuated strain with a G3A mutation within the 5′ UTR that is associated with increased sensitivity to type I interferons (IFNs), does not directly impact BBB permeability. Following intranasal infection of both wild-type and IFN-induced protein with tetratricopeptide repeats 1 (IFIT1)-deficient mice, which fail to block TC83-specific RNA translation, virus spreads to the olfactory bulb and cortex via migration along axonal tracts of neurons originating from the olfactory neuroepithelium. Global dissemination of virus in the CNS by 2 days post-infection (dpi) was associated with increased BBB permeability in the olfactory bulb, but not in the cortex or hindbrain, where permeability only increased after the recruitment of CX3CR1+ and CCR2+ mononuclear cells on 6 dpi, which corresponded with tight junction loss and claudin 5 redistribution. Importantly, despite higher levels of viral replication, similar results were obtained in IFIT1-deficient mice. These findings indicate that TC83 gains CNS access via anterograde axonal migration without directly altering BBB function and that mononuclear and endothelial cell interactions may underlie BBB disruption during alphavirus encephalitis.
- Published
- 2017
19. ILDR1 is important for paracellular water transport and urine concentration mechanism
- Author
-
Jianghui Hou, Susanne Milatz, Yongfeng Gong, Abby Sunq, Cosima Merkel, Nina Himmerkus, and Markus Bleich
- Subjects
Male ,0301 basic medicine ,Cell Membrane Permeability ,Vasopressins ,Receptors, Cell Surface ,Biology ,Aquaporins ,Kidney ,Tight Junctions ,Kidney Concentrating Ability ,Mice ,03 medical and health sciences ,medicine ,Animals ,Transcellular ,Kidney Tubules, Distal ,Mice, Knockout ,Aquaporin 2 ,Multidisciplinary ,Water transport ,Tight junction ,urogenital system ,Tricellular tight junction ,Biological Transport ,Epithelial Cells ,Biological Sciences ,Cell biology ,Kidney Tubules ,030104 developmental biology ,medicine.anatomical_structure ,Biochemistry ,Paracellular transport ,Knockout mouse ,Homeostasis - Abstract
Whether the tight junction is permeable to water remains highly controversial. Here, we provide evidence that the tricellular tight junction is important for paracellular water permeation and that Ig-like domain containing receptor 1 (ILDR1) regulates its permeability. In the mouse kidney, ILDR1 is localized to tricellular tight junctions of the distal tubules. Genetic knockout of Ildr1 in the mouse kidney causes polyuria and polydipsia due to renal concentrating defects. Microperfusion of live renal distal tubules reveals that they are impermeable to water in normal animals but become highly permeable to water in Ildr1 knockout animals whereas paracellular ionic permeabilities in the Ildr1 knockout mouse renal tubules are not affected. Vasopressin cannot correct paracellular water loss in Ildr1 knockout animals despite normal effects on the transcellular aquaporin-2-dependent pathway. In cultured renal epithelial cells normally lacking the expression of Ildr1, overexpression of Ildr1 significantly reduces the paracellular water permeability. Together, our study provides a mechanism of how cells transport water and shows how such a mechanism may be exploited as a therapeutic approach to maintain water homeostasis.
- Published
- 2017
20. Claudins in barrier and transport function—the kidney
- Author
-
Yongfeng Gong and Jianghui Hou
- Subjects
0301 basic medicine ,medicine.medical_specialty ,endocrine system diseases ,Physiology ,Clinical Biochemistry ,030232 urology & nephrology ,Gene Expression ,chemistry.chemical_element ,Calcium ,Biology ,urologic and male genital diseases ,digestive system ,Cell junction ,Article ,Tight Junctions ,Kidney Tubules, Proximal ,03 medical and health sciences ,0302 clinical medicine ,Physiology (medical) ,Internal medicine ,medicine ,Animals ,Humans ,Claudin ,Kidney ,Tight junction ,Renal sodium reabsorption ,urogenital system ,Reabsorption ,Membrane Proteins ,030104 developmental biology ,medicine.anatomical_structure ,Endocrinology ,chemistry ,Paracellular transport ,Claudins ,tissues - Abstract
Claudins are discovered to be key players in renal epithelial physiology. They are involved in developmental, physiological, and pathophysiological differentiation. In the glomerular podocytes, claudin-1 is an important determinant of cell junction fate. In the proximal tubule, claudin-2 plays important roles in paracellular salt reabsorption. In the thick ascending limb, claudin-14, -16, and -19 regulate the paracellular reabsorption of calcium and magnesium. Recessive mutations in claudin-16 or -19 cause an inherited calcium and magnesium losing disease. Synonymous variants in claudin-14 have been associated with hypercalciuric nephrolithiasis by genome-wide association studies (GWASs). More importantly, claudin-14 gene expression can be regulated by extracellular calcium levels via the calcium sensing receptor. In the distal tubules, claudin-4 and -8 form paracellular chloride pathway to facilitate electrogenic sodium reabsorption. Aldosterone, WNK4, Cap1, and KLHL3 are powerful regulators of claudin and the paracellular chloride permeability. The lessons learned on claudins from the kidney will have a broader impact on tight junction biology in other epithelia and endothelia.
- Published
- 2016
21. Introduction
- Author
-
Jianghui Hou
- Published
- 2019
22. Paracellular Water Channel
- Author
-
Jianghui Hou
- Subjects
Bicellular tight junction ,medicine.anatomical_structure ,Water channel ,Tight junction ,Chemistry ,Paracellular transport ,medicine ,Biophysics ,Tricellular tight junction ,Aquaporin ,Transcellular ,Epithelium - Abstract
Whether tight junction permeates water is highly controversial. Across both epithelium and endothelium, significant water permeability remains when transcellular water channels - aquaporins are removed from the plasma membrane. Tricellular tight junction is a new concept. Regular bicellular tight junctions cannot seal the tricellular corners. In fact, tricellular tight junction is made of two classes of proteins - tricellulin and angulins, which are different from the components of bicellular tight junction. Unlike the bicellular tight junction that only permeates small molecules with diameter of
- Published
- 2019
23. Perspective
- Author
-
Jianghui Hou
- Published
- 2019
24. Paracellular Cation Channel
- Author
-
Jianghui Hou
- Subjects
Chemistry ,Paracellular transport ,Biophysics ,Channel (broadcasting) - Published
- 2019
25. Paracellular Channel in Human Disease
- Author
-
Jianghui Hou
- Subjects
Positional cloning ,urogenital system ,Mutant ,Biology ,medicine.disease ,digestive system ,Phenotype ,Cell biology ,Channelopathy ,Paracellular transport ,medicine ,Allele ,Claudin ,tissues ,Gene - Abstract
Linkage analysis and positional cloning have led to the discovery of TJ genes and mutant alleles that cause various human diseases. More than 10 Mendelian diseases related to paracellular channel dysfunction have been solved on the molecular level. These include genetic disorders affecting the skin, the liver, the kidney, the inner ear, and the blood-brain barrier. In each case, identification of a gene sparks intense investigation of the cellular mechanism that can relate a genotype to a phenotype. Knowledge of the causal mechanism for disease not only facilitates the development of new treatment but also provides critical insight into the basic biology and physiology of paracellular channel. For example, the paracellular pathway in the kidney is particularly important for mineral metabolism. Genetic variations in three claudin genes, claudin-14, claudin-16, and claudin-19, are associated with renal diseases of Ca++ and Mg++ imbalance. Virtually every aspect of claudin biology, e.g. gene transcription, protein translation, trafficking, interaction, and transport function, plays an important role in paracellular channelopathy.
- Published
- 2019
26. Paracellular Anion Channel
- Author
-
Jianghui Hou
- Subjects
Chemistry ,Paracellular transport ,Biophysics ,Channel (broadcasting) ,Ion - Published
- 2019
27. Paracellular Channel Recording
- Author
-
Jianghui Hou
- Subjects
business.industry ,Paracellular transport ,Biophysics ,Medicine ,Channel (broadcasting) ,business - Published
- 2019
28. Paracellular Channel Formation
- Author
-
Jianghui Hou
- Subjects
Materials science ,Paracellular transport ,Biophysics ,Channel (broadcasting) - Published
- 2019
29. Paracellular Channel Evolution
- Author
-
Jianghui Hou
- Subjects
Physics ,Paracellular transport ,Biophysics ,Channel (broadcasting) - Published
- 2019
30. Paracellular Channel in Organ System
- Author
-
Jianghui Hou
- Subjects
Chemistry ,Paracellular transport ,Biophysics ,Channel (broadcasting) ,Organ system - Published
- 2019
31. A Laboratory Guide to the Tight Junction
- Author
-
Jianghui Hou and Jianghui Hou
- Subjects
- Laboratory Manual, Tight junctions (Cell biology), Tight Junctions
- Abstract
A Laboratory Guide to the Tight Junction offers broad coverage of the unique methods required to investigate its characteristics. The methods are described in detail, including its biochemical and biophysical principles, step-by-step process, data analysis, troubleshooting, and optimization. The coverage includes various cell, tissue, and animal models. Chapter 1 provides the foundations of cell biology of tight junction. Chapter 2 covers the Biochemical approaches for paracellular channels and is followed by chapter 3 providing the Biophysical approaches. Chapter 4 describes and discusses Histological approaches for tissue fixation and preparation. Chapter 5 discusses Light microscopy, while chapter 6 presents Electron microscopic approaches. Chapter 7 covers Transgenic manipulation in cell cultures, including DNA and siRNA, Mutagenesis, and viral infection. Chapter 8 covers transgenic manipulation in mice, including: Knockout, Knockin, siRNA knockdown, GFP/LacZ reporter, and overexpression. The final chapter discusses the future developments of new approaches for tight junction research. Researchers and advanced students in bioscience working on topics of cell junction, ion channel and membrane protein will benefit from the described methods. Clinicians and pathologists interested in tissue barrier diseases will also benefit from the biochemical and biophysical characterization of tight junctions in organ systems, and their connection to human diseases. Provides consistent and detailed research methods Covers various cell, tissue and animal models Includes step-by-step guidance from beginner to sophisticated levels
- Published
- 2020
32. Design of endonuclease restriction sites into primers for PCR cloning.
- Author
-
Jianghui Hou
- Published
- 2002
- Full Text
- View/download PDF
33. The Paracellular Channel : Biology, Physiology, and Disease
- Author
-
Jianghui Hou and Jianghui Hou
- Subjects
- Membrane proteins, Tight junctions (Cell biology), Membranes (Biology)
- Abstract
The Paracellular Channel: Biology, Physiology and Disease serves as the first volume to offer a cohesive and unifying picture of the critical functions of paracellular channels (tight junctions) in different tissues. This new class of ion channel utilizes a completely different mechanism to create ion passage pathways across the cell junction. This volume outlines common principles that govern the organization and regulation of these diverse cellular structures, describes the methodology of study, and highlights the pathophysiologic consequence of abnormal structure and functions of the paracellular channels in human diseases. Coverage includes biochemical, biophysical, structural, physiologic analyses of the paracellular channel, and new technologies for recording and characterization. Offers integrated coverage of all key aspects of the paracellular channel, an understudied field that may hold key insights into some of the most mysterious aspects of physiology Targets different levels of expertise, spanning from graduate students, interns and clinical fellows, to seasoned researchers that study functions, regulation and dysfunctions of different tissue barriers Provides a cohesive and unifying picture that describes the critical functions of paracellular channels (tight junctions) in different tissues
- Published
- 2019
34. Paracellular transport in the collecting duct
- Author
-
Jianghui Hou
- Subjects
0301 basic medicine ,endocrine system diseases ,Pseudohypoaldosteronism ,Blood Pressure ,urologic and male genital diseases ,digestive system ,Article ,Permeability ,Renal chloride reabsorption ,Tight Junctions ,03 medical and health sciences ,0302 clinical medicine ,Chlorides ,Internal Medicine ,medicine ,Animals ,Humans ,Claudin-4 ,Kidney Tubules, Collecting ,Claudin ,Adaptor Proteins, Signal Transducing ,Kidney ,Tight junction ,urogenital system ,Reabsorption ,Chemistry ,Microfilament Proteins ,Serine Endopeptidases ,Renal Reabsorption ,Cell biology ,030104 developmental biology ,medicine.anatomical_structure ,Nephrology ,Paracellular transport ,Claudins ,Kidney Diseases ,Carrier Proteins ,tissues ,030217 neurology & neurosurgery ,Homeostasis - Abstract
Purpose of review The paracellular pathway through the tight junction provides an important route for chloride reabsorption in the collecting duct of the kidney. This review describes recent findings of how defects in paracellular chloride permeation pathway may cause kidney diseases and how such a pathway may be regulated to maintain normal chloride homeostasis. Recent findings The tight junction in the collecting duct expresses two important claudin genes - claudin-4 and claudin-8. Transgenic knockout of either claudin gene causes hypotension, hypochloremia, and metabolic alkalosis in experimental animals. The claudin-4 mediated chloride permeability can be regulated by a protease endogenously expressed by the collecting duct cell - channel-activating protease 1. Channel-activating protease 1 regulates the intercellular interaction of claudin-4 and its membrane stability. Kelch-like 3, previously identified as a causal gene for Gordon's syndrome, also known as pseudohypoaldosteronism II, directly interacts with claudin-8 and regulates its ubiquitination and degradation. The dominant pseudohypoaldosteronism-II mutation (R528H) in Kelch-like 3 abolishes claudin-8 binding, ubiquitination, and degradation. Summary The paracellular chloride permeation pathway in the kidney is an important but understudied area in nephrology. It plays vital roles in renal salt handling and regulation of extracellular fluid volume and blood pressure. Two claudin proteins, claudin-4 and claudin-8, contribute to the function of this paracellular pathway. Deletion of either claudin protein from the collecting duct causes renal chloride reabsorption defects and low blood pressure. Claudins can be regulated on posttranslational levels by several mechanisms involving protease and ubiquitin ligase. Deregulation of claudins may cause human hypertension as exemplified in the Gordon's syndrome.
- Published
- 2016
35. Claudins and mineral metabolism
- Author
-
Jianghui Hou
- Subjects
0301 basic medicine ,Renal Tubular Transport, Inborn Errors ,endocrine system diseases ,Hypercalciuria ,030232 urology & nephrology ,chemistry.chemical_element ,Calcium ,Biology ,Kidney ,Nephrolithiasis ,urologic and male genital diseases ,digestive system ,Article ,Tight Junctions ,03 medical and health sciences ,0302 clinical medicine ,Internal Medicine ,medicine ,Humans ,Magnesium ,Claudin ,Calcium metabolism ,Tight junction ,urogenital system ,Kidney metabolism ,medicine.disease ,MicroRNAs ,Nephrocalcinosis ,030104 developmental biology ,medicine.anatomical_structure ,Biochemistry ,chemistry ,Nephrology ,Paracellular transport ,Claudins ,Receptors, Calcium-Sensing ,tissues ,Genome-Wide Association Study - Abstract
Purpose of review The tight junction conductance made of the claudin-based paracellular channel is important in the regulation of calcium and magnesium reabsorption in the kidney. This review describes recent findings of the structure, the function, and the physiologic regulation of claudin-14, claudin-16, and claudin-19 channels that through protein interactions confer calcium and magnesium permeability to the tight junction. Recent findings Mutations in two tight junction genes - claudin-16 and claudin-19 - cause the inherited renal disorder familial hypomagnesemia with hypercalciuria and nephrocalcinosis. A recent genome-wide association study has identified claudin-14 as a major risk gene of hypercalciuric nephrolithiasis. The crystal structure of claudin-19 has recently been resolved allowing the reconstruction of a claudin assembly model from cis-dimers made of claudin-16 and claudin-19 interaction. MicroRNAs have been identified as novel regulators of the claudin-14 gene. The microRNA-claudin-14 operon is directly regulated by the Ca sensing receptor gene in response to hypercalcemia. Summary The paracellular pathway in the kidney is particularly important for mineral metabolism. Three claudin proteins - claudin-14, claudin-16, and claudin-19 - contribute to the structure and function of this paracellular pathway. Genetic mutations and gene expression changes in these claudins may lead to alteration of the paracellular permeability to calcium and magnesium, ultimately affecting renal mineral metabolism.
- Published
- 2016
36. Biochemical and biophysical analyses of tight junction permeability made of claudin-16 and claudin-19 dimerization
- Author
-
Aparna Renigunta, Abby Sunq, Jing Yang, Vijayaram Renigunta, Lane A. Baker, Yongfeng Gong, Jinzhi Wang, Jianghui Hou, and Yi Zhou
- Subjects
Cell Membrane Permeability ,Cell membrane permeability ,endocrine system diseases ,Biophysics ,Biology ,urologic and male genital diseases ,Biochemistry ,Tight Junctions ,Humans ,Cell Interactions ,Claudin ,Molecular Biology ,Electron microscopic ,Tight junction permeability ,Tight junction ,urogenital system ,food and beverages ,Articles ,Cell Biology ,digestive system diseases ,3. Good health ,Cell biology ,Transmembrane domain ,Permeability (electromagnetism) ,Claudins ,Scanning ion-conductance microscopy ,Protein Multimerization - Abstract
Comprehensive biochemical, biophysical, genetic, and electron microscopic analyses of claudin-16 and -19 interactions show how claudin interaction can influence tight junction permeability and tight junction architecture., The molecular nature of tight junction architecture and permeability is a long-standing mystery. Here, by comprehensive biochemical, biophysical, genetic, and electron microscopic analyses of claudin-16 and -19 interactions—two claudins that play key polygenic roles in fatal human renal disease, FHHNC—we found that 1) claudin-16 and -19 form a stable dimer through cis association of transmembrane domains 3 and 4; 2) mutations disrupting the claudin-16 and -19 cis interaction increase tight junction ultrastructural complexity but reduce tight junction permeability; and 3) no claudin hemichannel or heterotypic channel made of claudin-16 and -19 trans interaction can exist. These principles can be used to artificially alter tight junction permeabilities in various epithelia by manipulating selective claudin interactions. Our study also emphasizes the use of a novel recording approach based on scanning ion conductance microscopy to resolve tight junction permeabilities with submicrometer precision.
- Published
- 2015
37. Corticomedullary difference in the effects of dietary Ca2+ on tight junction properties in thick ascending limbs of Henle’s loop
- Author
-
Adrian Klietz, Allein Plain, Nina Himmerkus, Susanne Milatz, Jianghui Hou, Markus Bleich, and Vera C. Wulfmeyer
- Subjects
0301 basic medicine ,Tight junction ,urogenital system ,Physiology ,Chemistry ,Reabsorption ,Clinical Biochemistry ,Renal Reabsorption ,Nephron ,03 medical and health sciences ,030104 developmental biology ,medicine.anatomical_structure ,Biochemistry ,Physiology (medical) ,Paracellular transport ,Loop of Henle ,medicine ,Biophysics ,Transcellular ,Claudin - Abstract
The thick ascending limb of Henle’s loop (TAL) drives an important part of the reabsorption of divalent cations. This reabsorption occurs via the paracellular pathway formed by the tight junction (TJ), which in the TAL shows cation selectivity. Claudins, a family of TJ proteins, determine the permeability and selectivity of this pathway. Mice were fed with normal or high-Ca2+ diet, and effects on the reabsorptive properties of cortical and medullary TAL segments were analysed by tubule microdissection and microperfusion. Claudin expression was investigated by immunostaining and quantitative PCR. We show that the TAL adapted to high Ca2+ load in a sub-segment-specific manner. In medullary TAL, transcellular NaCl transport was attenuated. The transepithelial voltage decreased from 10.9 ± 0.6 mV at control diet to 8.3 ± 0.5 mV at high Ca2+ load, thereby reducing the driving force for Ca2+ and Mg2+ uptake. Cortical TAL showed a reduction in paracellular Ca2+ and Mg2+ permeabilities from 8.2 ± 0.7 to 6.2 ± 0.5 ∙ 10−4 cm/s and from 4.8 ± 0.5 to 3.0 ± 0.2 · 10−4 cm/s at control and high-Ca2+ diet, respectively. Expression, localisation and regulation of claudins 10, 14, 16 and 19 differed along the corticomedullary axis: Towards the cortex, the main site of divalent cation reabsorption in TAL, high-Ca2+ intake led to a strong upregulation of claudin-14 within TAL TJs while claudin-16 and -19 were unaltered. Towards the inner medulla, only claudin-10 was present in TAL TJ strands. In summary, high-Ca2+ diet induced a reduction of divalent cation reabsorption via a diminution of NaCl transport and driving force in mTAL and via decreased paracellular permeabilities in cTAL. We reveal an important regulatory pattern along the corticomedullary axis and improve the understanding how the kidney disposes of detrimental excess Ca2+.
- Published
- 2015
38. Claudin-16 Deficiency Impairs Tight Junction Function in Ameloblasts, Leading to Abnormal Enamel Formation
- Author
-
Dominik N. Müller, Maria Morawietz, Dominique Bazin, Suzanne Menashi, Alain Schmitt, Jean Marc Massé, Marie Lucile Figueres, Agnès Linglart, Francisco de Assis Rocha Neves, Jianghui Hou, Rosa Vargas-Poussou, Ana Carolina Acevedo, Frédéric Courson, Dominique Le Denmat, Alejandro Garcia-Castaño, Matthias Petzold, Delphine Zenaty, Ariane Berdal, Julia Thumfart, Renato Demontis, Andreas Kiesow, Yong Wu, Maria Cristina Manzanares, Jean Christophe Fricain, Catherine Chaussain, Claire Bardet, Patricia Carvalho-Lobato, Georg Lorenz, Benoit Vallée, Sandy Ribes, Paulo Marcio Yamaguti, Mayssam Khaddam, Brigitte Baroukh, Deborah Talmud, Pascal Houillier, Thomas Guilbert, Benjamin Salmon, Tilman Breiderhoff, and Gaël Y. Rochefort
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Mutation ,Tight junction ,Enamel paint ,Chemistry ,Endocrinology, Diabetes and Metabolism ,Amelogenesis ,Matrix (biology) ,medicine.disease ,medicine.disease_cause ,stomatognathic diseases ,03 medical and health sciences ,030104 developmental biology ,Endocrinology ,stomatognathic system ,Internal medicine ,visual_art ,medicine ,visual_art.visual_art_medium ,Orthopedics and Sports Medicine ,Amelogenesis imperfecta ,Ameloblast ,Claudin - Abstract
Claudin-16 protein (CLDN16) is a component of tight junctions (TJ) with a restrictive distribution so far demonstrated mainly in the kidney. Here, we demonstrate the expression of CLDN16 also in the tooth germ and show that claudin-16 gene (CLDN16) mutations result in amelogenesis imperfecta (AI) in the 5 studied patients with familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC). To investigate the role of CLDN16 in tooth formation, we studied a murine model of FHHNC and showed that CLDN16 deficiency led to altered secretory ameloblast TJ structure, lowering of extracellular pH in the forming enamel matrix, and abnormal enamel matrix protein processing, resulting in an enamel phenotype closely resembling human AI. This study unravels an association of FHHNC owing to CLDN16 mutations with AI, which is directly related to the loss of function of CLDN16 during amelogenesis. Overall, this study indicates for the first time the importance of a TJ protein in tooth formation and underlines the need to establish a specific dental follow-up for these patients.
- Published
- 2015
39. Claudin-4 reconstituted in unilamellar vesicles is sufficient to form tight interfaces that partition membrane proteins
- Author
-
Jinzhi Wang, Brian Belardi, Daniel A. Fletcher, Jianghui Hou, Michael D. Vahey, and Sungmin Son
- Subjects
0301 basic medicine ,Molecular composition ,Proteolipids ,Short Report ,Biology ,Tight Junctions ,03 medical and health sciences ,Extracellular ,Humans ,Claudin-4 ,Cell adhesion ,Claudin ,Unilamellar Liposomes ,030304 developmental biology ,0303 health sciences ,Tight junction ,Chemistry ,Vesicle ,030302 biochemistry & molecular biology ,Cell Membrane ,Epithelial Cells ,Cell Biology ,Transmembrane protein ,030104 developmental biology ,Membrane ,Membrane protein ,Biophysics - Abstract
Tight junctions have been hypothesized to act as molecular fences in the plasma membrane of epithelial cells, helping to form differentiated apical and basolateral domains. While this fence function is believed to arise from the interaction of four-pass transmembrane claudins, the complexity of tight junctions has made direct evidence of their role as a putative diffusion barrier difficult to obtain. Here we address this challenge by reconstituting claudin-4 into giant unilamellar vesicles using microfluidic jetting. We find that reconstituted claudin-4 is sufficient to form adhesive interfaces between unilamellar vesicles without accessory proteins present in vivo. By controlling the molecular composition of the inner and outer leaflets of jetted membranes, we show that claudin-4-mediated interfaces can drive partitioning of extracellular membrane proteins but not of inner or outer leaflet lipids. Our findings indicate that homotypic interactions of claudins and their small size can contribute to the polarization of epithelial cells.
- Published
- 2018
40. Epigenetic Regulation of MicroRNAs Controlling CLDN14 Expression as a Mechanism for Renal Calcium Handling
- Author
-
Yongfeng Gong, Nina Himmerkus, Jianghui Hou, Allein Plain, and Markus Bleich
- Subjects
medicine.medical_specialty ,Hypoparathyroidism ,Hypercalciuria ,Naphthalenes ,Biology ,Kidney ,Epigenesis, Genetic ,Mice ,Internal medicine ,medicine ,Animals ,Gene silencing ,Magnesium ,Claudin ,Mice, Knockout ,Calcium metabolism ,Regulation of gene expression ,Hypocalcemia ,urogenital system ,General Medicine ,Cell biology ,Histone Deacetylase Inhibitors ,Mice, Inbred C57BL ,MicroRNAs ,Basic Research ,Endocrinology ,medicine.anatomical_structure ,Gene Expression Regulation ,Nephrology ,Paracellular transport ,Claudins ,Calcium ,Cinacalcet ,Histone deacetylase ,Calcium-sensing receptor ,Receptors, Calcium-Sensing - Abstract
The kidney has a major role in extracellular calcium homeostasis. Multiple genetic linkage and association studies identified three tight junction genes from the kidney--claudin-14, -16, and -19--as critical for calcium imbalance diseases. Despite the compelling biologic evidence that the claudin-14/16/19 proteins form a regulated paracellular pathway for calcium reabsorption, approaches to regulate this transport pathway are largely unavailable, hindering the development of therapies to correct calcium transport abnormalities. Here, we report that treatment with histone deacetylase (HDAC) inhibitors downregulates renal CLDN14 mRNA and dramatically reduces urinary calcium excretion in mice. Furthermore, treatment of mice with HDAC inhibitors stimulated the transcription of renal microRNA-9 (miR-9) and miR-374 genes, which have been shown to repress the expression of claudin-14, the negative regulator of the paracellular pathway. With renal clearance and tubule perfusion techniques, we showed that HDAC inhibitors transiently increase the paracellular cation conductance in the thick ascending limb. Genetic ablation of claudin-14 or the use of a loop diuretic in mice abrogated HDAC inhibitor-induced hypocalciuria. The genetic mutations in the calcium-sensing receptor from patients with autosomal dominant hypocalcemia (ADH) repressed the transcription of miR-9 and miR-374 genes, and treatment with an HDAC inhibitor rescued the phenotypes of cell and animal models of ADH. Furthermore, systemic treatment of mice with antagomiRs against these miRs relieved claudin-14 gene silencing and caused an ADH-like phenotype. Together, our findings provide proof of concept for a novel therapeutic principle on the basis of epigenetic regulation of renal miRs to treat hypercalciuric diseases.
- Published
- 2015
41. Characterization of Membrane Patch-Ion Channel Probes for Scanning Ion Conductance Microscopy
- Author
-
Lane A. Baker, Wenqing Shi, Jianghui Hou, Yucheng Xiao, Yuhan Zeng, Theodore R. Cummins, and Cheng Zhu
- Subjects
0301 basic medicine ,Microscopy ,Materials science ,Ion Transport ,Conductance ,General Chemistry ,Ion Channels ,Article ,Biomaterials ,03 medical and health sciences ,Transient receptor potential channel ,Barrel ,030104 developmental biology ,Membrane ,Scanning ion-conductance microscopy ,Biophysics ,Molecule ,General Materials Science ,Biosensor ,Porosity ,Ion channel ,Biotechnology - Abstract
Integration of dual-barrel membrane patch-ion channel probes (MP-ICPs) to scanning ion conductance microscopy (SICM) holds promise of providing a revolutionized approach of spatially-resolved chemical sensing. However, to fully exploit the MP-ICP platforms for concurrent topography and chemical sensing, a comprehensive characterization of the analytical performance of this newly-developed platform is needed. In this report, a series of experiments were performed to further our understanding of the system and to answer some fundamental questions, in preparation for future developments of this approach. First, we constructed MP-ICPs that contained different types of ion channels including TRPV1 and BK channels to establish the generalizability of the methods. Next, we proved the capability of the MP-ICP platforms in single ion channel activity measurements, and demonstrated that the channel behaviors can be faithfully obtained with this approach. In addition, we studied the interplay between the SICM barrel and the ICP barrel. For ion channels gated by uncharged ligands, channel activity at the ICP barrel is unaffected by the SICM barrel potential; whereas for ion channels that are gated by charged ligands, enhanced channel activity can be obtained by biasing the SICM barrel at potentials with opposite polarity to the charge of the ligand molecules. Finally, a proof-of-principle experiment was performed and site-specific molecular/ionic flux sensing was demonstrated at single-ion-channel level, which showed that the MP-ICP platform can be used to quantify local molecular/ionic concentrations.
- Published
- 2017
42. Parathyroid hormone controls paracellular Ca
- Author
-
Tadatoshi, Sato, Marie, Courbebaisse, Noriko, Ide, Yi, Fan, Jun-Ichi, Hanai, Jovana, Kaludjerovic, Michael J, Densmore, Quan, Yuan, Hakan R, Toka, Martin R, Pollak, Jianghui, Hou, and Beate, Lanske
- Subjects
Mice, Knockout ,urogenital system ,Extremities ,Tight Junctions ,Mice, Inbred C57BL ,Mice ,Gene Expression Regulation ,PNAS Plus ,Parathyroid Hormone ,Claudins ,Animals ,Calcium ,Promoter Regions, Genetic ,Receptor, Parathyroid Hormone, Type 1 ,Signal Transduction - Abstract
Renal calcium reabsorption is a critical process for maintaining systemic calcium homeostasis. Although the role of parathyroid hormone (PTH) in the regulation of transcellular Ca2+ reabsorption in distal convoluted tubules is well understood, its potential role in controlling the paracellular Ca2+ transport in the thick ascending limb of Henle (TAL) has not been investigated. We now present data demonstrating that PTH/PTHrP receptor (PTH1R) signaling directly and indirectly controls the levels of Claudin14 (CLDN14), a tight-junction protein responsible for paracellular Ca2+ transport in the TAL. Our findings suggest that down-regulation of Claudin14 could provide a potential treatment option to correct urinary Ca2+ loss, particularly in patients with hypoparathyroidism.
- Published
- 2017
43. Parathyroid hormone controls paracellular Ca 2+ transport in the thick ascending limb by regulating the tight-junction protein Claudin14
- Author
-
Marie Courbebaisse, Martin R. Pollak, Beate Lanske, Tadatoshi Sato, Hakan R. Toka, Jun-ichi Hanai, Noriko Ide, Jianghui Hou, Michael J. Densmore, Yi Fan, Jovana Kaludjerovic, and Quan Yuan
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Kidney ,Multidisciplinary ,Reabsorption ,030232 urology & nephrology ,chemistry.chemical_element ,Parathyroid hormone ,Calcium ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,medicine.anatomical_structure ,Endocrinology ,chemistry ,Internal medicine ,Paracellular transport ,medicine ,Transcellular ,Claudin ,Homeostasis - Abstract
Renal Ca2+ reabsorption is essential for maintaining systemic Ca2+ homeostasis and is tightly regulated through the parathyroid hormone (PTH)/PTHrP receptor (PTH1R) signaling pathway. We investigated the role of PTH1R in the kidney by generating a mouse model with targeted deletion of PTH1R in the thick ascending limb of Henle (TAL) and in distal convoluted tubules (DCTs): Ksp-cre;Pth1rfl/fl. Mutant mice exhibited hypercalciuria and had lower serum calcium and markedly increased serum PTH levels. Unexpectedly, proteins involved in transcellular Ca2+ reabsorption in DCTs were not decreased. However, claudin14 (Cldn14), an inhibitory factor of the paracellular Ca2+ transport in the TAL, was significantly increased. Analyses by flow cytometry as well as the use of Cldn14-lacZ knock-in reporter mice confirmed increased Cldn14 expression and promoter activity in the TAL of Ksp-cre;Pth1rfl/fl mice. Moreover, PTH treatment of HEK293 cells stably transfected with CLDN14-GFP, together with PTH1R, induced cytosolic translocation of CLDN14 from the tight junction. Furthermore, mice with high serum PTH levels, regardless of high or low serum calcium, demonstrated that PTH/PTH1R signaling exerts a suppressive effect on Cldn14. We therefore conclude that PTH1R signaling directly and indirectly regulates the paracellular Ca2+ transport pathway by modulating Cldn14 expression in the TAL. Finally, systemic deletion of Cldn14 completely rescued the hypercalciuric and lower serum calcium phenotype in Ksp-cre;Pth1rfl/fl mice, emphasizing the importance of PTH in inhibiting Cldn14. Consequently, suppressing CLDN14 could provide a potential treatment to correct urinary Ca2+ loss, particularly in patients with hypoparathyroidism.
- Published
- 2017
44. Claudin-14 Underlies Ca++-Sensing Receptor–Mediated Ca++ Metabolism via NFAT-microRNA–Based Mechanisms
- Author
-
Yongfeng Gong and Jianghui Hou
- Subjects
medicine.medical_specialty ,Calcineurin Inhibitors ,Hypercalciuria ,Naphthalenes ,Biology ,Kidney ,Mice ,Internal medicine ,medicine ,Animals ,Humans ,Claudin ,Calcium metabolism ,NFATC Transcription Factors ,Tight junction ,urogenital system ,Reabsorption ,NFAT ,General Medicine ,Cell biology ,Mice, Inbred C57BL ,MicroRNAs ,HEK293 Cells ,Basic Research ,medicine.anatomical_structure ,Endocrinology ,Gene Expression Regulation ,Nephrology ,Paracellular transport ,Claudins ,Calcium ,Signal transduction ,Receptors, Calcium-Sensing ,Signal Transduction - Abstract
Pathologic dysregulation of extracellular calcium metabolism is difficult to correct. The extracellular Ca(++)-sensing receptor (CaSR), a G protein-coupled receptor that regulates renal Ca(++) handling through changes in paracellular channel permeability in the thick ascending limb, has emerged as an effective pharmacological candidate for managing calcium metabolism. However, manipulation of CaSR at the systemic level causes promiscuous effects in the parathyroid glands, kidneys, and other tissues, and the mechanisms by which CaSR regulates paracellular transport in the kidney remain unknown. Here, we describe a CaSR-NFATc1-microRNA-claudin-14 signaling pathway in the kidney that underlies paracellular Ca(++) reabsorption through the tight junction. With CaSR-specific pharmacological reagents, we show that the in vivo gene expression of claudin-14 is regulated through a transcriptional mechanism mediated by NFATc1-microRNA and associated chromatin remodeling. Transgenic knockout and overexpression approaches showed that claudin-14 is required for CaSR-regulated renal Ca(++) metabolism. Together, our results define an important signaling cascade that, when dysregulated, may mediate Ca(++) imbalance through changes in tight junction permeability.
- Published
- 2014
45. Mosaic expression of claudins in thick ascending limbs of Henle results in spatial separation of paracellular Na+ and Mg2+ transport
- Author
-
Kerim Mutig, Nina Himmerkus, Dorothee Günzel, Susanne Milatz, Jianghui Hou, Hoora Drewell, Dominik N. Müller, Tilman Breiderhoff, Michael Fromm, Markus Bleich, and Vera C. Wulfmeyer
- Subjects
0301 basic medicine ,030232 urology & nephrology ,Biology ,digestive system ,Tight Junctions ,Rats, Sprague-Dawley ,03 medical and health sciences ,0302 clinical medicine ,Loop of Henle ,medicine ,Animals ,Humans ,Magnesium ,Claudin ,Mice, Knockout ,Multidisciplinary ,Tight junction ,Reabsorption ,urogenital system ,CLDN3 ,Sodium ,Transmembrane protein ,Mice, Inbred C57BL ,030104 developmental biology ,Ion homeostasis ,medicine.anatomical_structure ,HEK293 Cells ,Biochemistry ,PNAS Plus ,Paracellular transport ,Claudins ,Biophysics ,tissues - Abstract
The thick ascending limb (TAL) of Henle's loop drives paracellular Na+, Ca2+, and Mg2+ reabsorption via the tight junction (TJ). The TJ is composed of claudins that consist of four transmembrane segments, two extracellular segments (ECS1 and -2), and one intracellular loop. Claudins interact within the same (cis) and opposing (trans) plasma membranes. The claudins Cldn10b, -16, and -19 facilitate cation reabsorption in the TAL, and their absence leads to a severe disturbance of renal ion homeostasis. We combined electrophysiological measurements on microperfused mouse TAL segments with subsequent analysis of claudin expression by immunostaining and confocal microscopy. Claudin interaction properties were examined using heterologous expression in the TJ-free cell line HEK 293, live-cell imaging, and Forster/FRET. To reveal determinants of interaction properties, a set of TAL claudin protein chimeras was created and analyzed. Our main findings are that (i) TAL TJs show a mosaic expression pattern of either cldn10b or cldn3/cldn16/cldn19 in a complex; (ii) TJs dominated by cldn10b prefer Na+ over Mg2+, whereas TJs dominated by cldn16 favor Mg2+ over Na+; (iii) cldn10b does not interact with other TAL claudins, whereas cldn3 and cldn16 can interact with cldn19 to form joint strands; and (iv) further claudin segments in addition to ECS2 are crucial for trans interaction. We suggest the existence of at least two spatially distinct types of paracellular channels in TAL: a cldn10b-based channel for monovalent cations such as Na+ and a spatially distinct site for reabsorption of divalent cations such as Ca2+ and Mg2.
- Published
- 2016
46. Claudins and the Kidney
- Author
-
Madhumitha Rajagopal, Alan S.L. Yu, and Jianghui Hou
- Subjects
Cell Membrane Permeability ,endocrine system diseases ,Physiology ,Nephron ,Biology ,Kidney ,urologic and male genital diseases ,digestive system ,Article ,Tight Junctions ,Cell membrane ,medicine ,Loop of Henle ,Animals ,Humans ,Claudin ,Ion channel ,Tight junction ,urogenital system ,Biological Transport ,Cell biology ,medicine.anatomical_structure ,Membrane protein ,Paracellular transport ,Claudins ,Calcium ,Kidney Diseases ,tissues - Abstract
Claudins are tight junction membrane proteins that regulate paracellular permeability of renal epithelia to small ions, solutes, and water. Claudins interact within the cell membrane and between neighboring cells to form tight junction strands and constitute both the paracellular barrier and the pore. The first extracellular domain of claudins is thought to be the pore-lining domain and contains the determinants of charge selectivity. Multiple claudins are expressed in different nephron segments; such differential expression likely determines the permeability properties of each segment. Recent evidence has identified claudin-2 as constituting the cation-reabsorptive pathway in the proximal tubule; claudin-14, -16, and -19 as forming a complex that regulates calcium transport in the thick ascending limb of the loop of Henle; and claudin-4, -7, and -8 as determinants of collecting duct chloride permeability. Mutations in claudin-16 and -19 cause familial hypercalciuric hypomagnesemia with nephrocalcinosis. The roles of other claudins in kidney diseases remain to be fully elucidated.
- Published
- 2013
47. Capturing Rare Conductance in Epithelia with Potentiometric-Scanning Ion Conductance Microscopy
- Author
-
Lushan Zhou, Jianghui Hou, Abby Sunq, Yongfeng Gong, and Lane A. Baker
- Subjects
0301 basic medicine ,Potentiometric titration ,Analytical chemistry ,Epithelium ,Analytical Chemistry ,Madin Darby Canine Kidney Cells ,03 medical and health sciences ,0302 clinical medicine ,Dogs ,Canine kidney ,Microscopy ,medicine ,Animals ,Particle Size ,Tight junction ,Chemistry ,Madin Darby canine kidney cell ,Conductance ,030104 developmental biology ,medicine.anatomical_structure ,MARVEL Domain Containing 2 Protein ,Scanning ion-conductance microscopy ,Biophysics ,Potentiometry ,Microscopy, Electrochemical, Scanning ,030217 neurology & neurosurgery - Abstract
Tight junctions (TJs) are barrier forming structures of epithelia and can be described as tightly sealed intercellular spaces. Transport properties have been extensively studied for bicellular TJs (bTJs). Knowledge of the barrier functions of tricellular junctions (tTJs) are less well understood, due largely to a lack of proper techniques to locally measure discrete tTJ properties within a much larger area of epithelium. In this study, we use a nanoscale pipet to precisely locate tTJs within epithelia and measure the apparent local conductance of tTJs with a technique termed potentiometric scanning ion conductance microscopy (P-SICM). P-SICM shows the ability to differentiate transport through tTJs and bTJs, which was not possible with previous techniques and assays. We describe P-SICM investigations of both wild type and tricellulin overexpression Madin-Darby Canine Kidney (strain II, MDCKII) cells.
- Published
- 2016
48. Interaction between chromatin proteins MECP2 and ATRX is disrupted by mutations that cause inherited mental retardation
- Author
-
Skirmantas Kriaucionis, Jamal Nasir, Jianghui Hou, Xinhua Shu, Maria Jose Lafuente, Xinsheng Nan, Adrian Bird, and Alan W Maclean
- Subjects
X-linked Nuclear Protein ,congenital, hereditary, and neonatal diseases and abnormalities ,Methyl-CpG-Binding Protein 2 ,Rett syndrome ,medicine.disease_cause ,MECP2 ,Mice ,Intellectual Disability ,Two-Hybrid System Techniques ,mental disorders ,medicine ,Animals ,Humans ,ATRX ,Cells, Cultured ,Genetics ,Mutation ,DNA methylation ,Multidisciplinary ,biology ,Point mutation ,DNA Helicases ,Helicase ,Brain ,Nuclear Proteins ,DNA ,DNA Methylation ,Biological Sciences ,medicine.disease ,Chromatin ,nervous system diseases ,X-linked mental retardation ,Protein Transport ,biology.protein ,Protein Binding - Abstract
Mutations in the human methyl-CpG-binding protein gene MECP2 cause the neurological disorder Rett syndrome and some cases of X-linked mental retardation (XLMR). We report that MeCP2 interacts with ATRX, a SWI2/SNF2 DNA helicase/ATPase that is mutated in ATRX syndrome (α-thalassemia/mental retardation, X-linked). MeCP2 can recruit the helicase domain of ATRX to heterochromatic foci in living mouse cells in a DNA methylation-dependent manner. Also, ATRX localization is disrupted in neurons of Mecp2 -null mice. Point mutations within the methylated DNA-binding domain of MeCP2 that cause Rett syndrome or X-linked mental retardation inhibit its interaction with ATRX in vitro and its localization in vivo without affecting methyl-CpG binding. We propose that disruption of the MeCP2–ATRX interaction leads to pathological changes that contribute to mental retardation.
- Published
- 2016
49. Inducible Expression of Claudin-1 in Glomerular Podocytes Generates Aberrant Tight Junctions and Proteinuria through Slit Diaphragm Destabilization
- Author
-
Yongfeng Gong, Robyn Roth, Jianghui Hou, and Abby Sunq
- Subjects
0301 basic medicine ,Male ,endocrine system diseases ,Nephrosis ,Kidney Glomerulus ,urologic and male genital diseases ,Podocyte ,Tight Junctions ,Nephrin ,Rats, Sprague-Dawley ,03 medical and health sciences ,0302 clinical medicine ,Claudin-1 ,medicine ,Animals ,Claudin ,biology ,Tight junction ,urogenital system ,Podocytes ,General Medicine ,medicine.disease ,female genital diseases and pregnancy complications ,Cell biology ,Rats ,Proteinuria ,030104 developmental biology ,medicine.anatomical_structure ,Basic Research ,Nephrology ,Paracellular transport ,Immunology ,biology.protein ,Slit diaphragm ,Podocin ,030217 neurology & neurosurgery - Abstract
The tight junction (TJ) has a key role in regulating paracellular permeability to water and solutes in the kidney. However, the functional role of the TJ in the glomerular podocyte is unclear. In diabetic nephropathy, the gene expression of claudins, in particular claudin-1, is markedly upregulated in the podocyte, accompanied by a tighter filtration slit and the appearance of TJ-like structures between the foot processes. However, there is no definitive evidence to show slit diaphragm (SD) to TJ transition in vivo. Here, we report the generation of a claudin-1 transgenic mouse model with doxycycline-inducible transgene expression specifically in the glomerular podocyte. We found that induction of claudin-1 gene expression in mature podocytes caused profound proteinuria, and with deep-etching freeze-fracture electron microscopy, we resolved the ultrastructural change in the claudin-1–induced SD-TJ transition. Notably, immunolabeling of kidney proteins revealed that claudin-1 induction destabilized the SD protein complex in podocytes, with significantly reduced expression and altered localization of nephrin and podocin proteins. Mechanistically, claudin-1 interacted with both nephrin and podocin through cis- and trans-associations in cultured cells. Furthermore, the rat puromycin aminonucleoside nephrosis model, previously suspected of undergoing SD-TJ transition, exhibited upregulated expression levels of claudin-1 mRNA and protein in podocytes. Together, our data attest to the novel concept that claudins and the TJ have essential roles in podocyte pathophysiology and that claudin interactions with SD components may facilitate SD-TJ transition that appears to be common to many nephrotic conditions.
- Published
- 2016
50. The yin and yang of claudin-14 function in human diseases
- Author
-
Jianghui Hou
- Subjects
medicine.medical_specialty ,endocrine system diseases ,Tight junction ,urogenital system ,Endolymph ,General Neuroscience ,Biology ,Perilymph ,digestive system ,General Biochemistry, Genetics and Molecular Biology ,Cell biology ,medicine.anatomical_structure ,Endocrinology ,History and Philosophy of Science ,Internal medicine ,Paracellular transport ,medicine ,Inner ear ,sense organs ,Claudin ,tissues ,Cation transport ,Barrier function - Abstract
Claudins are tight junction integral membrane proteins that are key regulators of the paracellular pathway. The paracellular pathways in the inner ear and in the kidney are predominant routes for transepithelial cation transport. Mutations in claudin-14 cause nonsyndromic recessive deafness DFNB29. A recent genome-wide association study (GWAS) has identified claudin-14 as a major risk gene of hypercalciuric nephrolithiasis. In vitro analyses show claudin-14 functions as a cation barrier in epithelial cells. The barrier function of claudin-14 is crucial for generating the K+ gradient between perilymph and endolymph in the inner ear. However, neither homozygous individuals with DFNB29 mutations nor claudin-14 knockout mice show any renal dysfunction. In this review, I have discussed several possible mechanisms to integrate the physiological function of claudin-14 in the inner ear and the kidney.
- Published
- 2012
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.