Steven Boggess Email & Phone Number

Emeryville, Ca, Us

San Francisco, California, United States

Advisor: Professor Martin KampmannProject: Uncovering molecular mechanisms underlying neuronal hyperexcitability in tauopathies• I developed a pooled CRISPRi functional genomics FACS screen to identify modifiers of neuronal activity in human iPSC-derived neurons. Using a calcium-integration strategy, I demonstrated this screening paradigm positively identifies known regulators of synaptic excitability and connected disease-associated genes to neuronal excitability.• I validated hit genes from this screen with secondary FACS screens and individual sgRNA perturbations. I then collaborated with electrophysiologists at Genentech to characterize the electrophysiology of iPSC-neurons with knock-outs of these validated targets.• I used this pooled screening approach to screen the “druggable” genome for modifiers of synaptic excitability in wild-type tau neurons and neurons with a tau mutation associated with frontotemporal dementia (FTD). With these screens, we identified genotype-specific modifiers that specifically altered synaptic excitability in either the WT or tau-mutant neurons. These genetic modifiers may help to identify mechanisms that lead to the increased neuronal excitability observed in neurons with FTD associated tau mutations.• I contributed to and advised the development of a large-scale arrayed CRISPR screening platform for neuronal activity with voltage sensitive dyes and genetically encoded calcium indicators. In a collaborative effort with the Laboratory for Genomics Research (LGR), we prepared an arrayed lentiviral dual-sgRNA library targeting 50 neuronal genes, established a robust co-culture system with iPSC derived astrocytes and neurons, and characterized differences in neuronal activity patterns between WT and mutant-tau neurons with machine-learning approaches.• In collaboration with the LGR, I conducted a Perturb-seq screen in WT and mutant-tau neurons to characterize transcriptional changes leading to neuronal activity changes.

Berkeley, Ca

Advisor: Professor Evan W. MillerProject: Design, synthesize, and characterize chemical modifications to the molecular wire of VoltageFluor voltage-sensitive probes for optical measurement of cellular membrane potential.• I synthesized fluorene VoltageFluors (fVFs), a novel class of small-molecule voltage sensitive dyes, by exchanging the phenylene-vinylene molecular wire with a single fluorene unit. I further tuned the brightness and sensitivity of these probes by modifying the electron-rich aniline donor to affect the rate of photo-induced electron transfer (PeT)m which quenches the fluorescein dye head. These fVFs had reduced phototoxicity in cells compared to previous VFs.• I characterized fVFs with fluorescence spectroscopy and used dual microscopy-electrophysiology experiments to determine voltage sensitivity in HEK293 cells. I found that fVFs can report evoked and spontaneous action potentials in neonatal rat cortical neurons with good signal-to-noise. Furthermore, I found that fVFs could be used to evaluate changes to action potential shape and kinetics in iPSC-derived cardiomyocytes when treated with ion channel blockers and that recordings could be made for much longer without adverse phototoxicity effects.• I continued to develop fVFs by adding a vinylene spacer motif to the fluorene molecular wire. These vinylene-fluorene VFs (vf-VFs) had higher voltage sensitivity than fVFs and retained the beneficial gains in brightness and reduced phototoxicity.Project: Utilize VFs to record and predict the effects of cardiotoxic drug compounds on cardiac action potentials• I pioneered the use of VFs to optically measure cardiac action potentials in “organ-on-a-chip” devices and developed an analysis pipeline to characterize changes to optical action potential shape and kinetics. We used these tools to predict proarrhythmic risk of multiple pharmaceutical compounds. This work was performed in collaboration with Professor Kevin Healy, UC Berkeley.

Worked on a summer research project concerning organic synthesis methodology in the field of palladium catalyzed cross coupling. The fellowship spanned a period of 8 weeks. Attended Summer Undergraduate Research Conference at the University of California Irvine to participate in a poster presentation.

Provide direct basic patient care. Passed out food trays, helped with minor adjustments, assisted nursing staff with re-positioning and bathing. Communicated patient needs to health care staff. Worked in Telemetry, Sub-Acute, Radiology, and Emergency departments.

Doctor Of Philosophy (Ph.D.), Chemistry

Activities and Societies: Graduate Life CommitteeChemical Biology Graduate Program (NIH training grant)

Bachelor Of Science (Bs), Biochemistry And Molecular Biology