Low ph alters intracellular and extracellular communication in the acinar cell

Summary

Principal Investigator: ANAMIKA MARAGRET REED
Abstract: DESCRIPTION (provided by applicant): This proposal describes a five year training plan with the goal of developing the candidate into an independent investigator. The principal investigator will expand the scientific background and skills she has already attained through her research activities in the laboratory of Dr. Fred Gorelick, an expert in the molecular mechanisms of pancreatitis. By implementing a structured research, training, and career development plan under the mentorship of Dr. Gorelick and Dr. Michael Nathanson, an expert in calcium signaling in digestive epithelia, the candidate will gain the analytic framework, technical abilities, and knowledge base to succeed as an independent physician-scientist. Yale University and the Section of Digestive Diseases, with their rich network of diverse faculty and ample biomedical facilities, provide an ideal environment to pursue this plan. The pathogenesis of acute pancreatitis, a common and life-threatening disease, is incompletely understood. Clinical conditions characterized by acute acid loads predispose to the development of acute pancreatitis. Recently, the Gorelick lab has shown that low pH sensitizes to pancreatitis responses in vitro and in vivo. However, the mechanisms responsible for this sensitization are unknown. This proposal hypothesizes that low pH exerts its injurious effects by transforming intracellular calcium signaling and gap junctional intercellular communication in acinar cells from a physiologic pattern to one that causes pancreatitis. The specific aims of this proposal are to: 1) Determine the effects of low pH on intracellular calcium signaling in the acinar cell 2) Determine the effects of low pH on intercellular communication and 3) Determine whether acid-induced pancreatitis responses are mediated by pathologic calcium signals and/or changes in gap junctional intercellular communication. To establish the effects of low pH on calcium signals, isolated acinar cells will be examined through confocal microscopy. Functional aspects of gap junctional communication will be investigated by quantifying the degree of calcium signal synchrony and by examining dye transfer through gap junctions. Structural aspects of gap junctional intercellular communication will be examined by characterizing the degradation patterns of the predominant gap junction protein, connexin32. Finally, the role of calcium signals and gap junctional communication in acid-induced injury will be examined using in vitro and in vivo models of pancreatitis. Our preliminary data indicates that low pH decreases oscillation frequency and increases oscillation amplitude in isolated acini treated with physiologic concentrations of the cholecystokinin orthologue, cerulein. Additionally, low pH inhibits intercellular communication and leads to decreased levels of connexin32. Finally, we have found that inhibition of the ryanodine receptor, which mediates both the changes in calcium signaling and intercellular communication, reduces acid-induced zymogen activation and cellular injury in vitro. By establishing a link between harmful effects of acidemia and intracellular calcium signaling and intercellular gap junctional communication in the acinar cell, therapeutic strategies to treat or prevent acidosis-associated pancreatitis could be developed.
Funding Period: 2011-07-01 - 2016-06-30
more information: NIH RePORT

Top Publications

  1. pmc Low extracellular pH induces damage in the pancreatic acinar cell by enhancing calcium signaling
    Anamika M Reed
    Department of Internal Medicine, Section of Digestive Diseases, Yale University, New Haven, Connecticut 06515, USA
    J Biol Chem 286:1919-26. 2011
  2. pmc Low pH enhances connexin32 degradation in the pancreatic acinar cell
    Anamika M Reed
    Section of Digestive Diseases, Department of Internal Medicine, Yale University, New Haven, Connecticut
    Am J Physiol Gastrointest Liver Physiol 307:G24-32. 2014

Research Grants

Detail Information

Publications2

  1. pmc Low extracellular pH induces damage in the pancreatic acinar cell by enhancing calcium signaling
    Anamika M Reed
    Department of Internal Medicine, Section of Digestive Diseases, Yale University, New Haven, Connecticut 06515, USA
    J Biol Chem 286:1919-26. 2011
    ..These findings suggest that enhanced RYR-mediated Ca(2+) signaling in the basolateral region of the acinar cell is responsible for the injurious effects of low pHe on the exocrine pancreas...
  2. pmc Low pH enhances connexin32 degradation in the pancreatic acinar cell
    Anamika M Reed
    Section of Digestive Diseases, Department of Internal Medicine, Yale University, New Haven, Connecticut
    Am J Physiol Gastrointest Liver Physiol 307:G24-32. 2014
    ..These findings provide the first evidence that low extracellular pH can regulate gap junctional intercellular communication by enhancing connexin degradation...

Research Grants30

  1. Cellular Protein Involved in Trafficking of HIV-1
    Carol A Carter; Fiscal Year: 2013
    ..A strategy that should permit us to circumvent the lattr problem is development of anti-viral agents that target cellular proteins such as Tsg101 and endocytic machinery factors that play key roles in virus production. ..
  2. Semi-volatile PCBs: Sources, Exposures, Toxicities
    Larry W Robertson; Fiscal Year: 2013
    ..These data and dietary studies in the last Aim will provide a scientific basis for risk assessment and advice for stakeholders with the ultimate goal to protect highly-exposed individuals and populations. ..
  3. Calcium Signals Within Membrane Nanotubes
    Ian F Smith; Fiscal Year: 2013
    ....
  4. Physiology and pathophysiology of human pancreatic acinar cells
    Ashok K Saluja; Fiscal Year: 2013
    ..Once completed, the data generated from the proposed studies will lead to accelerated development of specific therapies against pancreatitis. ..
  5. Zymogen activation in pancreatitis
    Fred S Gorelick; Fiscal Year: 2013
    ..The findings of these studies could lead to modifications in intravenous solutions that optimize their effectiveness for the prevention and treatment of acute pancreatitis and provide insights into disease mechanisms. ) ..
  6. Trafficking mechanisms for secretory vesicles in pancreatic duct epithelial cells
    Duk Su Koh; Fiscal Year: 2013
    ..The experiments are broadly relevant to treatment of disorders of the digestive system. ..
  7. Dietary Regulation of Pancreatic Digestive Enzymes
    John A Williams; Fiscal Year: 2013
    ..Knowledge from this project should allow designing approaches to assist the human pancreas to regenerate and ensure an adequate supply of pancreatic digestive enzymes. ..
  8. ELECTROPHYSIOLOGY OF NEONATAL AND ADULT HEART
    Martin Morad; Fiscal Year: 2013
    ....
  9. CENTER FOR GASTROINTESTINAL BIOLOGY AND DISEASE
    Robert S Sandler; Fiscal Year: 2013
    ..Through all of its activities, the Center improves communication, promotes collaboration, develops careers and generally enriches the intellectual climate for digestive disease research. ..
  10. Gastointestinal Hormone Research Core Center
    Chung Owyang; Fiscal Year: 2013
    ..abstract_text> ..
  11. Autophagy and human islet amyloid polypeptide in animal models of type 2 diabetes
    Jacqueline Rivera; Fiscal Year: 2013
    ....
  12. Ethanol Regulates Vacuolar ATPase &PEDF
    Chuhan Chung; Fiscal Year: 2013
    ..We will selectively target v-ATPase subunits using molecular methods to determine whether this will inhibit pancreatic stellate cell and pancreatic cell growth in vivo. ..
  13. Internalization of gap junctions as a regulatory mechanism of direct GJIC
    Matthias M Falk; Fiscal Year: 2013
    ....
  14. Pathophysiology of Alveolar Epithelial Lung Injury
    Jacob I Sznajder; Fiscal Year: 2013
    ..The insights gained from the data generated from these studies will provide novel molecular targets for the development of new therapeutic strategies to treat patients with lung injury. ..
  15. Molecular Mechanisms of Acute Pancreatitis
    Craig D Logsdon; Fiscal Year: 2013
    ....