Faculty Bibliography

Organophosphates (OPs) are a class of neurotoxic acetylcholinesterase inhibitors including widely used pesticides as well as nerve agents such as VX and VR. Current treatment of these toxins relies on reactivating acetylcholinesterase, which remains ineffective. Enzymatic scavengers are of interest for their ability to degrade OPs systemically before they reach their target. Here we describe a library of computationally designed variants of phosphotriesterase (PTE), an enzyme that is known to break down OPs. The mutations G208D, F104A, K77A, A80V, H254G, and I274N broadly improve catalytic efficiency of VX and VR hydrolysis without impacting the structure of the enzyme. The mutation I106 A improves catalysis of VR and L271E abolishes activity, likely due to disruptions of PTE's structure. This study elucidates the importance of these residues and contributes to the design of enzymatic OP scavengers with improved efficiency.

Biological water-responsive (WR) materials are abundant in nature, and they are used as mechanical actuators for seed dispersal by many plants such as wheat awns and pinecones. WR biomaterials are of interest for applications as high-energy actuators, which can be useful in soft robotics or for capturing energy from natural water evaporation. Recent work on WR silk proteins has shown that β-sheet nanocrystalline domains with high stiffness correlate with the high WR actuation energy density, but the fundamental mechanisms to drive water responsiveness in proteins remain poorly understood. Here, we design, synthesize, and study protein block copolymers consisting of two α-helical domains derived from cartilage oligomeric matrix protein coiled-coil (C) flanking an elastin-like peptide domain (E), namely, CEC. We use these protein materials to create WR actuators with energy densities that outperform mammalian muscle. To elucidate the effect of structure on WR actuation, CEC was compared to a variant, CEC_L44A, in which a point mutation disrupts the α-helical structure of the C domain. Surprisingly, CEC_L44A outperformed CEC, showing higher energy density and less susceptibility to degradation after repeated cycling. We show that CEC_L44A exhibits a higher degree of intermolecular interactions and is stiffer than CEC at high relative humidity (RH), allowing for less energy dissipation during water responsiveness. These results suggest that strong intermolecular interactions and the resulting, relatively steady protein structure are important for water responsiveness.

Phosphotriesterases (PTEs) represent a class of enzymes capable of efficient neutralization of organophosphates (OPs), a dangerous class of neurotoxic chemicals. PTEs suffer from low catalytic activity, particularly at higher temperatures, due to low thermostability and low solubility. Supercharging, a protein engineering approach via selective mutation of surface residues to charged residues, has been successfully employed to generate proteins with increased solubility and thermostability by promoting charge-charge repulsion between proteins. We set out to overcome the challenges in improving PTE activity against OPs by employing a computational protein supercharging algorithm in Rosetta. Here, we discover two supercharged PTE variants, one negatively supercharged (with -14 net charge) and one positively supercharged (with +12 net charge) and characterize them for their thermodynamic stability and catalytic activity. We find that positively supercharged PTE possesses slight but significant losses in thermostability, which correlates to losses in catalytic efficiency at all temperatures, whereas negatively supercharged PTE possesses increased catalytic activity across 25°C-55°C while offering similar thermostability characteristic to the parent PTE. The impact of supercharging on catalytic efficiency will inform the design of shelf-stable PTE and criteria for enzyme engineering.

INTRODUCTION/BACKGROUND:There is a growing concern that certain public health restrictions imposed to prevent the spread of coronavirus disease 2019 (COVID-19) could result in more violence against women (VAW). We sought to determine if the rates and types of VAW changed during the COVID-19 pandemic at our level 1 trauma center (L1TC). METHODS:We performed a retrospective review of female patients who presented to our L1TC because of violence from 2019 through 2020. Patients were grouped into a pre-COVID or COVID period. The primary aim of this study was to compare rates of VAW between groups. Secondary aims sought to evaluate for any difference in traumatic mechanism between periods and to determine if a temporal relationship existed between COVID-19 and VAW rates. RESULTS:.01). CONCLUSION/CONCLUSIONS:Rates of VAW were unchanged between the pre-COVID and COVID periods, yet the odds of penetrating VAW were 5 times greater during the pandemic. Moving forward, trauma surgeons must remain vigilant for signs of violence and ensure that support services are available during future crises.

Alopecia areata (AA) is a common autoimmune disease with a lifetime risk of ∼2%. In AA, the immune system targets the hair follicle, resulting in clinical hair loss. The prognosis of AA is unpredictable, and currently there is no definitive treatment. Our previous whole genome expression studies identified active immune circuits in AA lesions, including common γ-chain cytokine and IFN pathways. Because these pathways are mediated through JAK kinases, we prioritized clinical exploration of small molecule JAK inhibitors. In preclinical trials in mice, tofacitinib successfully prevented AA development and reversed established disease. In our tofacitinib trial in 12 patients with moderate to severe AA, 11 patients completed a full course of treatment with minimal adverse events. Following limited response to the initial dose (5 mg b.i.d.), the dose was escalated (10 mg b.i.d.) for nonresponding subjects. Eight of 12 patients demonstrated ≥50% hair regrowth, while three patients demonstrated <50% hair regrowth, as measured by Severity in Alopecia Tool scoring. One patient demonstrated no regrowth. Gene expression profiles and Alopecia Areata Disease Activity Index scores correlated with clinical response. Our open-label studies of ruxolitinib and tofacitinib have shown dramatic clinical responses in moderate to severe AA, providing strong rationale for larger clinical trials using JAK inhibitors in AA. ClinicalTrials.gov ID NCT02299297.

Introduction: Monocarboxylate transporter 1 (MCT1) is an importer of monocarboxylates such as lactate and pyruvate and a marker of mitochondrial metabolism. MCT1 is highly expressed in a subgroup of cancer cells to allow for catabolite uptake from the tumor microenvironment to support mitochondrial metabolism. We studied the protein expression of MCT1 in a broad group of breast invasive ductal carcinoma specimens to determine its association with breast cancer subtypes and outcomes. Methods: MCT1 expression was evaluated by immunohistochemistry on tissue micro-arrays (TMA) obtained through our tumor bank. Two hundred and fifty-seven cases were analyzed: 180 cases were estrogen receptor and/or progesterone receptor positive (ER+ and/or PR+), 62 cases were human epidermal growth factor receptor 2 positive (HER2+), and 56 cases were triple negative breast cancers (TNBC). MCT1 expression was quantified by digital pathology with Aperio software. The intensity of the staining was measured on a continuous scale (0-black to 255-bright white) using a co-localization algorithm. Statistical analysis was performed using a linear mixed model. Results: High MCT1 expression was more commonly found in TNBC compared to ER+ and/or PR+ and compared to HER-2+ (p < 0.001). Tumors with an in-situ component were less likely to stain strongly for MCT1 (p < 0.05). High nuclear grade was associated with higher MCT1 staining (p < 0.01). Higher T stage tumors were noted to have a higher expression of MCT1 (p < 0.05). High MCT1 staining in cancer cells was associated with shorter progression free survival, increased risk of recurrence, and larger size independent of TNBC status (p < 0.05). Conclusion: MCT1 expression, which is a marker of high catabolite uptake and mitochondrial metabolism, is associated with recurrence in breast invasive ductal carcinoma. MCT1 expression as quantified with digital image analysis may be useful as a prognostic biomarker and to design clinical trials using MCT1 inhibitors.

Variously substituted indolin-2-ones were synthesized and evaluated for activity against KDR, Flt-1, FGFR-1 and PDGFR. Extension at the 5-position of the oxindole ring with ethyl piperidine (compound 7i) proved to be the most beneficial for attaining both biochemical and cellular potencies. Further optimization of 7i to balance biochemical and cellular potencies with favorable ADME/ PK properties led to the identification of 8h, a compound with a clean CYP profile, acceptable pharmacokinetic and toxicity profiles, and robust efficacy in multiple xenograft tumor models.