Michael Palladino, PhD
Professor of Pharmacology and Chemical BiologyE-mail
My lab studies neurological, neurodegenerative and mitochondrial diseases. We use Drosophila as a genetic model system, as well as mice and human cell culture to study progressive neurological and neuromuscular disorders. Recently the lab has developed numerous tractable fly models of human diseases and have a model of mitochondrial disease that represents the only such model with an endogenous mitochondrial mutation (mtATP6) amenable for study of this devastating class of disease. Currently the lab is focusing on elucidating the mechanism by which mutations affecting Na/K ATPase, triose phosphate isomerase (TPI), and ATP6 function result in RDP (rapid-onset dystonia parkinsonism), glycolytic enzymopathy, and mitochondrial encephalomyopathy, respectively.
Thru a collaboration with Drs. Hrizo and Brodsky we are using our fly model of TPI deficiency together with a yeast model that we developed to study the mechanism of protein degradation that underlies disease pathogenesis. Our studies have demonstrated that pathogenic mutations are those that retain isomerase function but increase protein turnover, typically by destabilizing the dimer interface. Thus, disease pathogenesis results when functional protein is degraded by cytosolic protein quality control pathways, which recognize the protein as mutant. Our current studies leverage our results of an RNAi screen that identified ~ 35 modulators of TPI turnover, including many novel proteins not previously known to function in protein quality control. Identifying the molecular basis of mutant protein recognition and degradation will elucidate novel pathways that are therapeutic targets for these diseases.
Thru our collaboration with Dr. Levitan’s lab we are studying the basis of neuropathogenesis. Among glycolytic enzymopathies TPI deficiency has the most severe neurological symptoms. We have shown that TPI Deficiency mutants can be genetically complemented with mutations lacking isomerase activity. This could suggest that TPI has a novel non-catalytic role in the nervous system. We have discovered a defect in synaptic vesicle dynamics associated with TPI deficiency, likely explaining the neurologic dysfunction associated with this disease. Does this result due to a loss of a novel TPI function? How does TPI accumulate at the synapse and does its function assist the targeting of synaptic vesicles to the terminals? Our studies of neuropathogenesis will answer these questions and explain the molecular basis of genetic complementation with a catalytically inactive TPI isoform.
Currently we are using our models of these disease to understand pathogenesis with the goal of identifying novel avenues of therapy, performing drug and compound screens to identify efficacious drugs and combination therapies, and developing novel gene therapy approaches for mitochondrial diseases.
• Drosophila genetics, disease modeling and genomic engineering
• Genetic modifier screens to identify novel suppression/therapeutic pathways
• Directed and unbiased compound screening in vivo
• Mitochondrial disease gene therapy approaches
• In vivo research in flies and in vitro studies in fly and human cells
|PhD||Genetics||University of Connecticut||2000|
|Postdoc||Neurogenetics||University of Wisconsin||2003|
|Assistant Professor of Pharmacology||University of Pittsburgh School of Medicine||2003-2008|
|Assistant Professor of Pharmacology and Chemical Biology||University of Pittsburgh School of Medicine||2008-2015|
|Professor of Pharmacology and Chemical Biology||University of Pittsburgh School of Medicine||2015-present|
Honors and awards
1996-1997 Elizabeth and Keith Funston Scholarship (Trinity)
1996-1997 Mary A. Terry Fellow (Trinity)
1996 J. Wendell Burger Prize in Biology (Trinity)
1997 ACS, Division of Polymer Chemistry Award (Trinity)
1997 Class Salutatorian (Trinity)
1997 Graduation Summa Cum Laude (Trinity)
1997 Departmental and Deans Honors (Trinity)
1998 NSF Predoctoral Fellowship, Honorable Mention (UCHC)
2000 Irwin H. Lepow Graduate Fellowship Award (UCHC)
2000 Larry Sandler Genetics Award Finalist (UCHC)
2001 Daymon Runyon-Walter Winchell Postdoctoral Fellowship (Declined)
2001 Jane Coffin Childs Medical Research Fellowship Award (U.Wisc.)
2006-2009 American Heart Association, Scientist Development Award (U.Pitt.)
Palladino, M.J. and B. Ganetzky. Neurodegeneration mutants, method for identifying same,
and method for screening for neuroprotective agents. Patent 7060249B2. Awarded June 13, 2006.
Blondel, M., Couplan, E., Di Rago, J-P., Dauzonne, D., Palladino, M., Celotto, A. Compounds for the treatment of mitochondrial diseases. Patent IB2010001006. Awarded December 05, 2011.
Palladino A.M. and M.J. Palladino. Mitochondrial RNA import as a novel gene therapy. 8,883,755 B2. Awarded Nov 11, 2014.
Service on NIH MNG panel as ad hoc reviewer (06/09, 10/09, 02/10, 06/10). Regular member of the United Mitochondrial Disease Foundation study section (2008-2011). Ad hoc grant review for the Pepper Center's Pilot and Experimental Studies at the University of Michigan (2007). Motor Neurone Disease Association (2007 & 2008). University of Padua intramural grant review (2007). The National Center for the replacement, refinement and reduction of animals in research (NC3Rs; 2009). NIH MNG regular member 07/2010-06/2014. Ad Hoc review Wellcome Trust (2012). NIH ZRG1 ETTN-H (2012). NIH MDCN-N, Review Panel Chair (2012). NSF MCB 1244623 reviewer (2012). NIH ETTN-03 Neuroscience SEP (2013). United Mitochondrial Disease Foundation study section co-chair (2011-2015), NIH ZRG1 ETTN-G (2013), Chronic Fatigue Initiative review panel (2014-2015). Friedreich's Ataxia Research Alliance (FARA) grant review (2014). NIH-NOMD ad Hoc reviewer (2014-2015).
Palladino, Michael J., Liam P. Keegan, Mary A. O’Connell and Robert A. Reenan (2000). A-to-I pre-mRNA editing in Drosophila is primarily involved in adult nervous system function and integrity. Cell 102, 437-449.
Palladino, Michael J., Liam P. Keegan, Mary A. O’Connell and Robert A. Reenan (2000). Drosophila double-stranded RNA-specific adenosine deaminase is highly developmentally regulated and is itself a target for RNA editing. RNA 6, 1004-1018. PMCID:PMC1369976.
Celotto, Alicia M., Adam C. Frank, Steven W. McGrath, Timothy J. Fergestad, Wayne A. Van Voorhies, Karolyn Buttle, Carmen A. Mannella and Michael J. Palladino (2006). Mitochondrial Encephalomyopathies in Drosophila. Journal of Neuroscience 26, 810-820.
Seigle, Jacquelyn L., Alicia M. Celotto, and Michael J. Palladino (2008). Degradation of functional TPI protein underlies sugarkill neuropathology. GENETICS 179, 855-862. PMCID:PMC2429879.
Roland, Bartholomew P., Kimberly A. Stuchul, Samantha B. Larsen, Christopher G. Amrich, Andrew P. VanDemark, Alicia M. Celotto, Michael J. Palladino (2013). Evidence of a triosephosphate isomerase non-catalytic function crucial to behavior and longevity. Journal of Cell Science, Jul 15; 126:3151-8. PMCID: PMC3711204.
Towheed, Atif, Desiree M. Markantone, Aaron T. Crain, Alicia M. Celotto, Michael J. Palladino (2014). Small mitochondrial-targeted RNAs modulate endogenous mitochondrial protein expression in vivo. Neurobiology of Disease, 69;15-22. PMCID: PMC4106415.
Roland, Bartholomew P., Christopher G. Amrich, Charles J. Kammerer, Kimberly A. Stuchul, Samantha B. Larsen, Sascha Rode, Anoshé A. Aslam, Annie Heroux, Ronald Wetzel, Andrew P. VanDemark, and Michael J. Palladino (2014). Triosephosphate Isomerase I170V Alters Catalytic Site, Enhances Stability and Induces Pathology in a Drosophila Model of TPI Deficiency. BBA-Disease. Biochimica et Biophysica Acta: Molecular Basis of Disease, 1852 (2015) 61–69. PMCID in process.
My research focuses on the mechanism(s) by which specific small RNAs are imported into mitochondria. Additionally, I am investigating possible mechanisms and factors such as chaperones and other proteins or RNAs that facilitate import and translation in the mitochondria using human cell culture and Drosophila melanogaster.
My research focus is the basis of the neuropathology of mitochondrial encephalomyopathy (ME), using the Drosophila ATP6 model. The progressive seizures experienced by human patients of ME are inexplicably difficult to treat with commonly used anti-epileptic drugs, highlighting the need for studies that will yield alternative pharmacological targets. The ATP6 fly also experiences progressive seizures, as well as other hallmarks of pathological excitability such as reduced sleep, abnormal neuronal depolarization, and increased neuronal stimulus response.
My research focuses on tracking the degradation of TPI along motor neurons in drosophila larvae using a GFPtimer. TPI pathogenesis results from a faster turnover rate due to mutation. Transport and degradation of TPI can be observed in real time using a GFPtimer, which is a fluorescent protein that changes color from blue to red over time. When both mutant and wild-type GFP-tagged TPI are expressed in Drosophila larvae, the florescent timer can be used to better understand the transport and degradation of TPI.
I have been studying various ion channels, such as Shaker, Hyperkinetic, EAG-channels and KATP pumps, to determine if they might play as significant role in the seizure pathogenesis that is part of mitochondrial disease. Through stress-induced seizures, and the measurements thereof, I am trying to narrow down when exactly these channels and related mechanisms might be taking a turn for the worse. While drug screens for possible alleviating chemicals are a part of this project, I have also been examining the Ketogenic Diet and its effects on our Drosophila model.
My Research focuses on identifying important proteasome pathway factors involved in the degradation of Triose Phosphate Isomerase Sugarkill (TPIsgk). We are using a drosophila model to screen 500 different RNA interference constructs that knock down the expression of chaperones, transcription factors, and cytosolic proteins with unknown function in hopes of discovering components of the pathway. My other research involves studying genomic constructs involving Shab and KV-2.1 to learn more about their roles in neuroprotection and neurodegeneration.
My research currently is a part of the collaboration with Drs. Hrizo and Brodsky. I assist in completing all the steps of the RNAi screen, from setting up the appropriate fly matings to obtain the desired genotypes, to organizing the data and passing it along to Drs. Hrizo and Brodsky for further analysis.
My research uses green fluorescent protein (GFP) variants to investigate the dimerization of the TPI protein. GFP and its related forms are used to construct chimeric fluorescent-tagged mutant and wild type TPI protein dimers that can be analyzed using FRET in a Drosophila model.