Cyclic nucleotide permeability of connexin mutants related to genetic disease

Summary

Principal Investigator: Virginijus Valiunas
Abstract: DESCRIPTION (provided by applicant): Gap junctions provide a direct intercellular pathway for cell-to-cell signaling and impulse conduction and play an important role in normal physiology. However, mutations in their connexin proteins have been implicated in many hereditary diseases, including nervous system disorders, deafness, cataracts and some skin diseases. Mutations in connexin43 (Cx43) have been linked to oculodentodigital dysplasia (ODDD) which manifests with bone deformities and accompanying neurological complications. In another case, Cx40 mutations have been correlated with atrial fibrillation and other arrhythmias. Most of the disease associated mutations are single amino acid substitutions and we hypothesize that they could potentially alter the specific perm-selectivity properties of the affected connexin channel. We wish to quantify second messenger permeability for wild-type Cx43 and Cx40 and compare them to human mutations of Cx43 and Cx40 associated with ODDD and arrhythmia. The cyclic nucleotides, cAMP and cGMP are of particular interest as both are important in normal bone development and play a role in cardiac myocyte contractility and pacing. In Aim1 the perm-selectivity properties of gap junction channels formed by Cx40 and Cx43 to second messengers cAMP and cGMP will be determined. A reporter gene SpIH will be used to monitor cAMP/cGMP permeability while simultaneously monitoring junctional conductance by dual whole cell patch clamp. Aim2 will determine the cyclic nucleotide perm-selectivity properties of gap junction channels formed by disease linked mutations in Cx40 (A96S, M163V and G38D) and Cx43 (L90V, I130T and K134E). We will quantify and compare the permeability of gap junction channels formed by mutated connexins to their wild-type counterparts. Aim3 will characterize the intercellular trafficking, gating properties and perm-selectivity properties of gap junction channels formed by Cx40 and Cx43 mutants. We will test for changes in channel open probability, voltage and pH dependent gating, intercellular trafficking and permeability as these parameters represent alternative ways that mutations could diminish the magnitude of cell-to-cell communication. In this proposal, the cyclic nucleotide perm-selectivity of wild-type and disease associated mutant connexins will be compared qualitatively and quantitatively. The results of the proposed research will establish a baseline for understanding the role of perm-selectivity as a potential determinant of disease states such as ODDD and atrial fibrillation. Based on the results of Aims 1-3, we will determine which channel properties (perm-selectivity, open probability, or trafficking) are responsible for functional alterations in mutated connexins. PUBLIC HEALTH RELEVANCE: Gap junctions play an important role in normal physiology and mutations in their connexin proteins have been implicated in many human hereditary diseases. This proposal seeks to evaluate the perm-selectivity of wild-type and disease associated mutant connexins qualitatively and quantitatively, including permeability to known signaling molecules like cyclic nucleotides. The results of the proposed research will establish a baseline for understanding the role of perm-selectivity as a potential determinant of disease states such as oculodentodigital dysplasia and atrial fibrillation.
Funding Period: 2011-05-01 - 2016-04-30
more information: NIH RePORT

Top Publications

  1. pmc Stimulating cardiac muscle by light: cardiac optogenetics by cell delivery
    Zhiheng Jia
    Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794 8181, USA
    Circ Arrhythm Electrophysiol 4:753-60. 2011
  2. pmc The Cx26-G45E mutation displays increased hemichannel activity in a mouse model of the lethal form of keratitis-ichthyosis-deafness syndrome
    Gulistan Mese
    Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, USA
    Mol Biol Cell 22:4776-86. 2011
  3. pmc MATLAB implementation of a dynamic clamp with bandwidth of >125 kHz capable of generating I Na at 37 °C
    Chris Clausen
    Department of Physiology and Biophysics and Institute for Molecular Cardiology, Health Sciences Center, Stony Brook University, Stony Brook, NY 11794 8661, USA
    Pflugers Arch 465:497-507. 2013
  4. pmc Human articular chondrocytes express multiple gap junction proteins: differential expression of connexins in normal and osteoarthritic cartilage
    Maria D Mayan
    Osteoarticular and Aging Research Group, Rheumatology Division, INIBIC Hospital Universitario A Coruña, A Coruna, Spain
    Am J Pathol 182:1337-46. 2013
  5. pmc Cyclic nucleotide permeability through unopposed connexin hemichannels
    Virginijus Valiunas
    Department of Physiology and Biophysics, Stony Brook University Stony Brook, NY, USA
    Front Pharmacol 4:75. 2013

Research Grants

  1. Connexin Distribution in Physiological Versus Pathological Cardiac Hypertrophy
    Michael R Zile; Fiscal Year: 2013
  2. Mechanisms of Gap Junction Regulation
    Paul L Sorgen; Fiscal Year: 2013
  3. Internalization of gap junctions as a regulatory mechanism of direct GJIC
    Matthias M Falk; Fiscal Year: 2013
  4. STRUCTURAL ANALYSIS OF GAP JUNCTION TRAFFICKING
    Gina E Sosinsky; Fiscal Year: 2013
  5. PHOSPHORYLATION OF GAP JUNCTION PROTEINS
    Paul D Lampe; Fiscal Year: 2013
  6. Endogenous Cannabinoids and Brain Function
    Aron H Lichtman; Fiscal Year: 2013
  7. Regulation of Osteoblast Differentiation and Function by Connexin 43
    Joseph P Stains; Fiscal Year: 2013
  8. Signaling in Inflammation, Stress, and Tumorigenesis
    GEORGE ROBERT STARK; Fiscal Year: 2013
  9. STRUCTURE AND DYNAMICS OF CONNEXIN26 GAP JUNCTIONS
    Gina E Sosinsky; Fiscal Year: 2013
  10. EINSTEIN AGING STUDY
    Richard B Lipton; Fiscal Year: 2013

Detail Information

Publications6

  1. pmc Stimulating cardiac muscle by light: cardiac optogenetics by cell delivery
    Zhiheng Jia
    Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794 8181, USA
    Circ Arrhythm Electrophysiol 4:753-60. 2011
    ..However, functionality of optogenetic tools has not been fully explored outside neuroscience, and a nonviral, nonembryogenesis-based strategy for optogenetics has not been shown before...
  2. pmc The Cx26-G45E mutation displays increased hemichannel activity in a mouse model of the lethal form of keratitis-ichthyosis-deafness syndrome
    Gulistan Mese
    Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, USA
    Mol Biol Cell 22:4776-86. 2011
    ..These results confirm the pathogenic nature of the G45E mutation and provide a new model for studying the role of aberrant connexin hemichannels in epidermal differentiation and inherited connexin disorders...
  3. pmc MATLAB implementation of a dynamic clamp with bandwidth of >125 kHz capable of generating I Na at 37 °C
    Chris Clausen
    Department of Physiology and Biophysics and Institute for Molecular Cardiology, Health Sciences Center, Stony Brook University, Stony Brook, NY 11794 8661, USA
    Pflugers Arch 465:497-507. 2013
    ....
  4. pmc Human articular chondrocytes express multiple gap junction proteins: differential expression of connexins in normal and osteoarthritic cartilage
    Maria D Mayan
    Osteoarticular and Aging Research Group, Rheumatology Division, INIBIC Hospital Universitario A Coruña, A Coruna, Spain
    Am J Pathol 182:1337-46. 2013
    ....
  5. pmc Cyclic nucleotide permeability through unopposed connexin hemichannels
    Virginijus Valiunas
    Department of Physiology and Biophysics, Stony Brook University Stony Brook, NY, USA
    Front Pharmacol 4:75. 2013
    ..The data presented here show that hemichannels of Cx43 and Cx26 are permeable to cAMP, and further the data suggest that hemichannels are, in fact, a potential pathway for cAMP mediated cell-to-cell signaling...

Research Grants30

  1. Connexin Distribution in Physiological Versus Pathological Cardiac Hypertrophy
    Michael R Zile; Fiscal Year: 2013
    ..pathological hypertrophy, with ex- tensively characterized cytoskeletal properties in each setting. ..
  2. Mechanisms of Gap Junction Regulation
    Paul L Sorgen; Fiscal Year: 2013
    ....
  3. Internalization of gap junctions as a regulatory mechanism of direct GJIC
    Matthias M Falk; Fiscal Year: 2013
    ....
  4. STRUCTURAL ANALYSIS OF GAP JUNCTION TRAFFICKING
    Gina E Sosinsky; Fiscal Year: 2013
    ..We investigate the connexin43 trafficking process using an imaging based approach examining the hierarchy of connexin43 phosphorylation events and where within the cell cycle, connexin43-kinase(s) interactions occurs. ..
  5. PHOSPHORYLATION OF GAP JUNCTION PROTEINS
    Paul D Lampe; Fiscal Year: 2013
    ....
  6. Endogenous Cannabinoids and Brain Function
    Aron H Lichtman; Fiscal Year: 2013
    ..Ultimately, the knowledge gained from this basic research will yield novel therapeutic targets that can be exploited with the pharmacological agents developed here. PROGRAM CHARACTERISTICS ..
  7. Regulation of Osteoblast Differentiation and Function by Connexin 43
    Joseph P Stains; Fiscal Year: 2013
    ..Indeed, understanding the coordination of osteoblast, osteocyte and osteoclasts networks is vital to the understanding nearly all diseases of skeletal metabolism. ..
  8. Signaling in Inflammation, Stress, and Tumorigenesis
    GEORGE ROBERT STARK; Fiscal Year: 2013
    ..abstract_text> ..
  9. STRUCTURE AND DYNAMICS OF CONNEXIN26 GAP JUNCTIONS
    Gina E Sosinsky; Fiscal Year: 2013
    ..The proposed research is significant because results will be useful in defining better drugs and other therapeutics that potentially ameliorate connexin-related diseases. ..
  10. EINSTEIN AGING STUDY
    Richard B Lipton; Fiscal Year: 2013
    ..Together, these Projects will help disentangle the multifactorial processes that lead to cognitive and locomotor decline and dementia. ..
  11. Structure and Dynamics of Gap Junction Channels
    MARK JAY YEAGER; Fiscal Year: 2013
    ..Such a detailed molecular picture will provide insight into how these channels are involved in such diverse processes as regulating the heartbeat and hereditary deafness. ..