The Seth Blackshaw Lab uses functional genomics and proteomics to rapidly identify the molecular mechanisms that regulate cell specification and survival in both the retina and hypothalamus. We have profiled gene expression in both these tissues, from the start to the end of neurogenesis, characterizing the cellular expression patterns of more than 1,800 differentially expressed transcripts in both tissues. Working together with the lab of Heng Zhu in the Department of Pharmacology, we have also generated a protein microarray comprised of nearly 20,000 unique full-length human proteins, which we use to identify biochemical targets of developmentally important genes of interest.

Our lab is focused on using comprehensive gene expression, methylation and sequencing and metabolomics analysis to identify alterations in breast cancer, and exploiting these for early detection and therapy. Among deferentially expressed genes, our lab has focused on the HOX genes. HOX genes are intimately involved in the development of resistance to both chemotherapy and to agents targeting the estrogen receptor. Our work explores the alternate pathways that are activated by HOX proteins leading to this resistance and novel treatments to overcome resistance in both tissue culture and xenograft models. In addition, epigenetically silenced genes and a metabolic reprogramming in tumors also trigger novel early detection and therapeutic strategies. We are testing the utility of differentiation therapy through reactivating RAR-beta in breast cancer using histone deacetylase inhibitors with great success. Also, we are targeting enzymes involved in gluconeogenesis and glycolysis with small molecule FDA-approved antimetabolites to achieve antitumor effects.

The Paul Worley Lab examines the molecular basis of learning and memory. In particular, we cloned a set of immediate early genes (IEGs) that are rapidly transcribed in neurons involved in information processing, and that are essential for long term memory. IEG proteins can directly modify synapses and provide insight into cellular mechanisms that support synapse-specific plasticity.

Research in the Alex Kolodkin Laboratory is focused on understanding how neuronal connectivity is established during development. Our work investigates the function of extrinsic guidance cues and their receptors on axonal guidance, dendritic morphology and synapse formation and function. We have investigated how neural circuits are formed and maintained through the action of guidance cues that include semaphorin proteins, their classical plexin and neuropilin receptors, and also novel receptors. We employ a cross-phylogenetic approach, using both invertebrate and vertebrate model systems, to understand how guidance cues regulate neuronal pathfinding, morphology and synaptogenesis. We also seek to understand how these signals are transduced to cytosolic effectors. Though broad in scope, our interrogation of the roles played by semaphorin guidance cues provides insight into the regulation of neural circuit assembly and function. Our current work includes a relatively new interest in understanding the origins of laminar organization in the central nervous system.

The Advanced Optics Lab uses innovative optical tools, including laser-based nanotechnologies, to understand cell motility and the regulation of cell shape. We pioneered laser-based nanotechnologies, including optical tweezers, nanotracking, and laser-tracking microrheology. Applications range from physics, pharmaceutical delivery by phagocytosis (cell and tissue engineering), bacterial pathogens important in human disease and cell division. Other projects in the lab are related to microscopy, specifically combining fluorescence and electron microscopy to view images of the subcellular structure around proteins.

Our research is focused on understanding the basic mechanisms of programmed cell death in disease pathogenesis. Billions of cells die per day in the human body. Like cell division and differentiation, cell death is also critical for normal development and maintenance of healthy tissues. Apoptosis and other forms of cell death are required for trimming excess, expired and damaged cells. Therefore, many genetically programmed cell suicide pathways have evolved to promote long-term survival of species from yeast to humans. Defective cell death programs cause disease states. Insufficient cell death underlies human cancer and autoimmune disease, while excessive cell death underlies human neurological disorders and aging. Of particular interest to our group are the mechanisms by which Bcl-2 family proteins and other factors regulate programmed cell death, particularly in the nervous system, in cancer and in virus infections. Interestingly, cell death regulators also regulate many other cellular processes prior to a death stimulus, including neuronal activity, mitochondrial dynamics and energetics. We study these unknown mechanisms. We have reported that many insults can trigger cells to activate a cellular death pathway (Nature, 361:739-742, 1993), that several viruses encode proteins to block attempted cell suicide (Proc. Natl. Acad. Sci. 94: 690-694, 1997), that cellular anti-death genes can alter the pathogenesis of virus infections (Nature Med. 5:832-835, 1999) and of genetic diseases (PNAS. 97:13312-7, 2000) reflective of many human disorders. We have shown that anti-apoptotic Bcl-2 family proteins can be converted into killer molecules (Science 278:1966-8, 1997), that Bcl-2 family proteins interact with regulators of caspases and regulators of cell cycle check point activation (Molecular Cell 6:31-40, 2000). In addition, Bcl-2 family proteins have normal physiological roles in regulating mitochondrial fission/fusion and mitochondrial energetics to facilitate neuronal activity in healthy brains.

Work in the Green Lab is centered on the ribosome. The overall fidelity of protein synthesis appears to be limited by the action of the ribosome, which is the two-subunit macromolecular machine responsible for decoding and translating messenger RNAs (mRNAs) into protein in all organisms. Our work is divided into four general project areas. The longest-standing research area concerns the interactions of eubacterial ribosomes and release factors. The goal is to understand the mechanism of action of release factors on the ribosome. A second research area involves biochemical and structure/function studies of the miRNA pathway, particularly the mechanism of action of the Argonaute proteins and their interacting factors. A third area of work in the lab is centered around regulation of eukaryotic translation, specifically in understanding the mechanism behind various mRNA quality control pathways and the interactions of proteins therein, as well as with the ribosome. The newest area of research in the lab extends our strengths in ribosome biochemistry to characterize the translation status of the cell using the ribosome profiling. We are using this technique to better understand the role of several factors involved in eukaryotic and prokaryotic translation fidelity.

The CRCIF was established to foster collaborative efforts aimed at elucidating the role of intermediate filaments (IFs) in the heart. Intermediate filaments constitute a class of cytoskeletal proteins in metazoan cells, however, different from actin microfilaments and tubulin microtubules, their function in cardiac cells is poorly understood. Unique from the other two components of the cytoskeleton, IFs are formed by cell type-specific proteins. Desmin is the main component of the IFs in the cardiac myocytes. We measured the consistent induction of desmin post-translational modifications (PTMs, such as phosphorylation, etc.) in various clinical and experimental models of heart failure. Therefore, one of our main focuses is to determine the contribution of desmin PTMs to the development of heart failure in different animal and clinical models. Active Projects: • Quantification of desmin PTM-forms in different forms of heart failure at the peptide level using mass spectrometry • Functional assessment of the role of desmin PTMs in heart failure development using single site mutagenesis and biophysical methods • Molecular characterization of desmin preamyloid oligomers using mass spectrometry, in vitro and in vivo imaging • Assessment of the diagnostic and pharmacological value of desmin PTMs in heart failure development

The Johns Hopkins Center for Epithelial Disorders focuses on research into the physiology and pathophysiology of epithelial cells (cells that line the cavities and interior surfaces of the body) of the gastrointestinal (GI) tract, liver, pancreas and kidney. Specifically, the center’s research seeks to: -Understand the mechanisms regulating the activity of transport proteins (including channels) of epithelial cells Characterize the mechanisms by which polarity of epithelial cells are maintained -Investigate the mechanisms controlling transcription of epithelial-specific genes Understand the pathophysiological basis of GI and renal diseases that involve the preceding three components -The center also provides a framework for training fellows in gastroenterology and hepatology to become independent investigators. The center is funded primarily through individual investigator-initiated extramural research grant support from the National Institutes of Health (NIH) as well as multi-investigator grants including RO1, PO1, UO1 and R24.

Current projects include: The evaluation of mechanisms of immune tolerance to cancer in mouse models of breast and pancreatic cancer. We have characterized the HER-2/neu transgenic mouse model of spontaneous mammary tumors. This model demonstrates immune tolerance to the HER-2/neu gene product. This model is being used to better understand the mechanisms of tolerance to tumor. In addition, this model is being used to develop vaccine strategies that can overcome this tolerance and induce immunity potent enough to prevent and treat naturally developing tumors. More recently, we are using a genetic model of pancreatic cancer developed to understand the early inflammatory changes that promote cancer development. The identification of human tumor antigens recognized by T cells. We are using a novel functional genetic approach developed in our laboratory. Human tumor specific T cells from vaccinated patients are used to identify immune relevant antigens that are chosen based on an initial genomic screen of overexpressed gene products. Several candidate targets have been identified and the prevelence of vaccine induced immunity has been assessed . This rapid screen to identify relevant antigenic targets will allow us to begin to dissect the mechanisms of tumor immunity induction and downregulation at the molecular level in cancer patients. More recently, we are using proteomics to identify proteins involved in pancreatic cancer development. We recently identified Annexin A2 as a molecule involved in metastases. The analysis of antitumor immune responses in patients enrolled on vaccine studies. The focus is on breast and pancreatic cancers. We are atttempting to identify in vitro correlates of in vivo antitumor immunity induced by vaccine strategies developed in the laboratory and currently under study in the clinics.