Clifford Steer, MD

Research Techniques:

Light, confocal and electron microscopy; Immunostaining and morphometric analysis; FACS analysis; Northern, western and Southern blotting; Isolation of nuclei, polysomes and mitochondria; Run-on transcription, in vitro RNA decay and RNase protection; Electrophoretic mobility gel shifts; Microarrrays; Tissue culture both primary and cell lines; Reporter gene assays - luciferase and CAT; PCR, RT-PCR, quantitative PCR and RT-PCR, real-time PCR; Apoptosis detection: TUNEL, annexin, mitochondrial and caspase assays; Plasmid and transgene construction using the Sleeping Beauty transposon system; Nonviral transgene and oligonucleotide delivery for gene augmentation and repair; Biochemical assays for gene activity - specific to model system being studied; Protein production and purification

Research Interests:

The Steer laboratory is involved in two major areas of research. In the first, the lab has over the last six years developed a novel gene therapy that involves the precise repair of genetic defects in cells. The lab has concentrated on the genetic repair of a variety of diseases, including hemophilia, sickle cell disease, Crigler-Najjar syndrome type I, ornithine transcarbamylase deficiency, ß-thalassemia, von Willebrand’s disease and certain neurodegenerative disorders like Huntington’s disease. In fact, Steer has successfully treated several accurate animal models for these human disorders. The technology of gene repair is remarkable for its broad application. The ability to now correct a genetic sequence in combination with the knowledge from the human genome project creates a remarkable vista of potential therapeutic clinical studies. The correction of a precise genetic defect allows the gene to be endogenously regulated without the potential problems associated with viral vectors. It may provide us with the first cures to diseases such as sickle cell and hemophilia. The Steer lab has successfully elucidated the basic science and will now apply the technology as therapy for human disease. In addition, the lab has also developed a more traditional type of gene therapy for diseases that are not candidates for genetic repair. However, while it is just as powerful as any traditional approach, it does not require potentially harmful viral vectors. The future of gene therapy is non-viral and that is the focus of our research as it applies to human therapy.

In the second area research, Steer has discovered that ursodeoxycholic acid, an endogenous hydrophilic bile acid in humans, is a potent antiapoptotic agent. Several animal models have been for diseases that are relatively accurate to their human counterparts. Specifically, ursodeoxycholic acid as a therapeutic agent to treat models of Huntington’s disease, head trauma, acute stroke, as well as Parkinson’s disease. One common characteristic shared by these disorders as well as others is the role that apoptosis plays in disease progression. Bile acid has been determined as a potent antiapoptotic agent, significantly improves neurologic status in these models. In the basic science studies, the lab has delineated the molecular mechanism by which ursodeoxycholic acid acts to preserve cell survival and cell function. As a therapeutic agent, ursodeoxycholic acid is unique in that it is a natural bile acid with no toxicity, crosses the blood-brain barrier, and can be delivered easily to patients. There are, in fact, many disease states that could potentially benefit, including myocardial infarction, autoimmune diseases, and the many acute and chronic neurodegenerative disorders for which there is little available treatment.

Selected Publications:

Amaral JD, Viana RJS, Ramalho RM, Steer CJ, and Rodrigues CMP:  Bile acids: regulation of apoptosis by ursodeoxycholic acid.  J Lipid Res, in press.

Wang X, Sarkar DP, Mani P, Steer CJ, Chen Y, Guha C, Chandrasekhar V, Chaudhuri A, Roy-Chowdhury N, Kren BT, and Roy-Chowdhury J:  Long-term reduction of jaundice in Gunn rats by non-viral liver-targeted delivery of Sleeping Beauty transposon.  Hepatology, in press.

Aravalli RN, Steer CJ, Sahin B, and Cressman ENK: Stem cell origins and animal models of hepatocellular carcinoma. Dig Dis Sci, in press

Kren BT, Unger GM, Sjeklocha L, Trossen AA, Korman V, Diethelm-Okita BM, Reding MT, and Steer CJ: Nanocapsule-delivered Sleeping Beauty mediates therapeutic FVIII expression in liver sinusoidal endothelial cells of hemophilia A mice. J Clin Invest, in press.

Aranha MM, Sol S, Low WC, Steer CJ, and Rodrigues CMP: Caspases and p53 modulate FOXO3A/Id1 signaling during mouse neural stem cell differentiation. J Cell Biochem 107:748-758, 2009.

Wang L, Oberg AL, Asmann YW, Sicotte H, McDonnell SK, Riska SM, Liu W, Steer CJ, Subramanian S, Cunningham JM, Cerhan JR, and Thibodeau SN: Genome-wide transcriptional profiling reveals microRNA-correlated genes and biological processes in human lymphoblastoid cell lines. PLoS ONE 4(6):e5878, 2009

Kren BT, Wong PY-P, Sarver A, Zhang X, Zeng Y, and Steer CJ: microRNAs identified in highly purified liver-derived mitochondria may play a role in apoptosis. RNA Biol 6:65-72, 2009

Bruzzone CM, Belcher JD, Schuld NJ, Newman KA, Vineyard J, Nguyen J, Chen C, Beckman JD, Steer CJ, and Vercellotti GM: Quantitative real-time polymerase chain reaction (qRT-PCR) restriction fragment length polymorphism (RFLP) method for monitoring highly conserved transgene expression during gene therapy. Transl Res 152:290-297, 2008.

Aravalli RN, Steer CJ, and Cressman ENK: Molecular mechanisms of hepatocellular carcinoma. Hepatology 48:2047-2063, 2008.

Ramalho RM, Viana RS, Castro RE, Steer CJ, Low WC, and Rodrigues CMP: Apoptosis in transgenic mice expressing the P301L mutated form of human tau. Mol Med 14:309-317, 2008

Wangensteen KJ, Wilber A, Keng VW, He Z, Matise I, Wangensteen L, Carson CM, Chen Y, Steer CJ, McIvor RS, Largaespada DA, Wang X, and Ekker SC: A facile method for somatic, lifelong manipulation of multiple genes in the mouse liver. Hepatology 47:1714-1724, 2008

Ramalho RM, Viana RJS, Low WC, Steer CJ, and Rodrigues CMP: Bile acids and apoptosis modulation: an emerging role in experimental Alzheimer's disease. Trends Mol Med 14:54-62, 2008.

Amaral JD, Castro RE, Sol S, Steer CJ, and Rodrigues CMP: p53 is a key molecular target of ursodeoxycholic acid in regulating apoptosis. J Biol Chem 282:34250-34259, 2007.

Castro RE, Sol S, Steer CJ, and Rodrigues CMP: Bile acids as modulators of apoptosis. In Sahu SC (Ed): Hepatotoxicity: From Genomics to in vitro and in vivo Models, Wiley & Sons, Ltd, 2007, pp. 391-419

Castro RE, Amaral JD, Sol S, Kren BT, Steer CJ, and Rodrigues CMP: Differential regulation of cyclin D1 and cell death by bile acids in primary rat hepatocytes. Am J Physiol Gastrointest Liver Physiol 293:G327-G334, 2007

Amaral JD, Sol S, Steer CJ, and Rodrigues CMP: Function of nuclear steroid receptors in apoptosis: role of ursodeoxycholic acid. Expert Rev Endocrinol Metab 2:487-501, 2007.

Zhu J, Kren BT, Park CW, Bilgim R, Wong PY-P, and Steer CJ: Erythroid-specific expression of ?-globin by the Sleeping Beauty transposon for sickle cell disease. Biochemistry 46:6844-6858, 2007

To view these and other publications visit http://www.ncbi.nlm.nih.gov/PubMed
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