Butterworth Lab Department of Cell Biology University of Pittsburgh
Butterworth LabDepartment of Cell BiologyUniversity of Pittsburgh


What We Do 

(Potential graduate student projects listed)


Research Focus 1 


Role of non-coding RNAs in hormonal regulation of sodium transport in the kidney


We are investigating the regulation of non-coding RNA including long non-coding (lncRNA) and microRNAs (miRNAs) by several hormones. We use a range of techniques to investigate the effect of hormones on miRNA regulation in the kidney, and identify new protein targets that alter ion transport. 


Graduate Student Projects 

1) miRNA knockout mice and sodium regulation in the kidney

2) Analysis of DeepSeq/RNASeq data to identify hormonally regulated miRNAs and lncRNAs in the kidney.

3) Physiological characterization miR targets in aldosterone-mediated ENaC regulation.

4) Role of insulin in miR regulation in the distal nephron, links to diabetes

Research Focus 2 


Regulation of microRNAs by long non-coding RNA sponges


A role for microRNAs (miRs) has been established in growth, development, physiology and disease. Almost 2000 human miRs have been identified, and they act primarily to repress protein expression by binding to the untranslated region of mRNA to prevent protein translation and accelerate mRNA degradation (see schematic below). Far less studied are the long-ncRNAs (lncRNA) > 200bp in length. Several functions have been attributed to lncRNAs. They are able to interact with proteins, DNA and RNA in both the cytoplasm and nucleus to influence gene expression, translation or alter protein function. These studies aim to investigate whether lncRNA expression is regulated by hormonal signals, and if they scavenge smaller RNA species as an additional layer of gene regulation. Studies will focus on the idea that lncRNAs can act as miR sponges as a modifier of miR function.


Graduate Student Projects 

1) Deep sequencing/microarray and computational approaches to predict and validate lncRNA-miR interactions.

2) Interrupting hormonal signaling by altering lncRNA expression.

3) Using tagged miRs as bait to pull out lncRNA interactors (by deep-seq and PCR)

Research Focus 3 


ENaC trafficking in kidney epithelia


The major research interest investigates the regulation of ENaC by trafficking and recycling mechanisms. We investigate the regulation of ENaC in 2 tissues, the distal kidney nephron where upregulation of the channel is associated with volume expansion and hypertension, and human airway where ENaC is linked to cystic fibrosis. 


In understanding how cells move this channel around when required (normally by hormonal or local signaling cues) we have focused on the role of small GTPases, deubiquitylating enzymes (DUBs) and most recently microRNAs. 


The work has been expanded to include other distal nephron transporters namely, aquaporin 2, ROMK (potassium channel) and the Sodium Chloride Co-transporter (NCC) to see if what we observe for ENaC regulation is applicable to these other transporters found in the same segment of the kidney nephron.


Graduate Student Projects

1) The mechanisms of intersectin 2 in the regulation of ENaC. 

2) Small GTPases and ENaC regulation. Investigating novel Rab proteins that may be involved in ENaC trafficking and recycling in mCCD cells.

3) Ubiquitylation and ENaC trafficking. Mapping the ubiquitin ligases and deubiquitylating enzymes that impact ENaC (a project I call, "A day in the life of ENaC")

4) Cytoskeletal and motor proteins and ENaC trafficking

5) Disease-linked mutations in ENaC

Research Focus 4 


Regulation of ENaC in the cystic fibrosis airway



The epithelial sodium channel (ENaC) is responsible for the movement of sodium and water, across epithelial membranes. ENaC activity is increased by the action of proteases which cleave its extracellular loops to activate the channel. A proposed role for ENaC in the human airway is the maintenance of airway fluid homeostasis and regulation of airway surface liquid (ASL) height. One hypothesis to account for decreased ASL height and airway dehydration in CF is inappropriate upregulation of ENaC due to an imbalance in protease activity. Bacterial proteases may therefore contribute to virulence by increasing proteolytic activation of ENaC and reducing mucociliary clearance, which would facilitate colonization. The work is carried out in collaboration with Dr Patrick Thibodeau in the Department of Microbiology and Molecular Genetics.


Potential Graduate Student Projects Related to Focus 4

1) Investigating the role of proteases in human airway epithelial cells.

2) The role of secreted proteases, ENaC activity and Pseudomonas colonization in cystic fibrosis.

Contact Us

Department of Cell Biology

S314 SBT
200 Lothrop St, Pittsburgh, PA

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Michael Butterworth, PhD