Publications

Development of a sleeve gastrectomy-induced metabolite as therapy for T2D and obesity

Bariatric surgery reveals a gut-restricted TGR5 agonist with anti-diabetic effects

Snehal N. Chaudhari, David A. Harris, Hassan Aliakbarian, James N. Luo, Matthew T. Henke, Renuka Subramaniam, Ashley H. Vernon, Ali Tavakkoli, Eric G. Sheu & A. Sloan Devlin

Abstract: Bariatric surgery, the most effective treatment for obesity and type 2 diabetes, is associated with increased levels of the incretin hormone glucagon-like peptide-1 (GLP-1) and changes in levels of circulating bile acids. The levels of individual bile acids in the gastrointestinal (GI) tract after surgery have, however, remained largely unstudied. Using ultra-high performance liquid chromatography-mass spectrometry-based quantification, we observed an increase in an endogenous bile acid, cholic acid-7-sulfate (CA7S), in the GI tract of both mice and humans after sleeve gastrectomy. We show that CA7S is a Takeda G-protein receptor 5 (TGR5) agonist that increases Tgr5 expression and induces GLP-1 secretion. Furthermore, CA7S administration increases glucose tolerance in insulin-resistant mice in a TGR5-dependent manner. CA7S remains gut restricted, minimizing off-target effects previously observed for TGR5 agonists absorbed into the circulation. By studying changes in individual metabolites after surgery, the present study has revealed a naturally occurring TGR5 agonist that exerts systemic glucoregulatory effects while remaining confined to the gut.

PubMed

Development of an inexpensive at-home influenza kit and detectio

An enhanced isothermal amplification assay for viral detection

Jason Qian, Sarah A. Boswell, Christopher Chidley, Zhi-xiang Lu, Mary E. Pettit, Benjamin L. Gaudio, Jesse M. Fajnzylber, Ryan T. Ingram, Rebecca H. Ward, Jonathan Z. Li, Michael Springer

Abstract: Rapid, inexpensive, robust diagnostics are essential to control the spread of infectious diseases. Current state of the art diagnostics are highly sensitive and specific, but slow, and require expensive equipment. Here we report the development of a molecular diagnostic test for SARS-CoV-2 based on an enhanced recombinase polymerase amplification (eRPA) reaction. eRPA has a detection limit on patient samples down to 5 viral copies, requires minimal instrumentation, and is highly scalable and inexpensive. eRPA does not cross-react with other common coronaviruses, does not require RNA purification, and takes ~45 min from sample collection to results. eRPA represents a first step toward at-home SARS-CoV-2 detection and can be adapted to future viruses within days of genomic sequence availability. 

PubMed

Small molecule modulators of gut bacterial bile acid metabolism to treat metabolic syndrome and associated NAFLD

Development of a covalent inhibitor of gut bacterial bile salt hydrolases

Arijit A. Adhikari, Tom C. M. Seegar, Scott B. Ficarro, Megan D. McCurry, Deepti Ramachandran, Lina Yao, Snehal N. Chaudhari, Sula Ndousse-Fetter, Alexander S. Banks, Jarrod A. Marto, Stephen C. Blacklow, and A. Sloan Devlin

Abstract: Bile salt hydrolase (BSH) enzymes are widely expressed by human gut bacteria and catalyze the gateway reaction leading to secondary bile acid formation. Bile acids regulate key metabolic and immune processes by binding to host receptors. There is an unmet need for a potent tool to inhibit BSHs across all gut bacteria to study the effects of bile acids on host physiology. Here, we report the development of a covalent pan-inhibitor of gut bacterial BSHs. From a rationally designed candidate library, we identified a lead compound bearing an alpha-fluoromethyl ketone warhead that modifies BSH at the catalytic cysteine residue. This inhibitor abolished BSH activity in conventional mouse feces. Mice gavaged with a single dose of this compound displayed decreased BSH activity and decreased deconjugated bile acid levels in feces. Our studies demonstrate the potential of a covalent BSH inhibitor to modulate bile acid composition in vivo.

PubMed

Development of small molecule modulators of autophagy and ER stress as novel therapeutics for AD

Modulating TRADD to restore cellular homeostasis and inhibit apoptosis

Daichao Xu, Heng Zhao, Minzhi Jin, Hong Zhu, Bing Shan, Jiefei Geng, Slawomir A. Dziedzic, Palak Amin, Lauren Mifflin, Masanori Gomi Naito, Ayaz Najafov, Jing Xing, Lingjie Yan, Jianping Liu, Ying Qin, Xinqian Hu, Huibing Wang, Mengmeng Zhang, Vica Jean Manuel, Li Tan, Zhuohao He, 5, Zhenyu J. Sun, Virginia M. Y. Lee, Gerhard Wagner, and Junying Yuan

Abstract: Cell death in human diseases is often a consequence of disrupted cellular homeostasis. If cell death is prevented without restoring cellular homeostasis, it may lead to a persistent dysfunctional and pathological state. Although mechanisms of cell death have been thoroughly investigated1-3, it remains unclear how homeostasis can be restored after inhibition of cell death. Here we identify TRADD4-6, an adaptor protein, as a direct regulator of both cellular homeostasis and apoptosis. TRADD modulates cellular homeostasis by inhibiting K63-linked ubiquitination of beclin 1 mediated by TRAF2, cIAP1 and cIAP2, thereby reducing autophagy. TRADD deficiency inhibits RIPK1-dependent extrinsic apoptosis and proteasomal stress-induced intrinsic apoptosis. We also show that the small molecules ICCB-19 and Apt-1 bind to a pocket on the N-terminal TRAF2-binding domain of TRADD (TRADD-N), which interacts with the C-terminal domain (TRADD-C) and TRAF2 to modulate the ubiquitination of RIPK1 and beclin 1. Inhibition of TRADD by ICCB-19 or Apt-1 blocks apoptosis and restores cellular homeostasis by activating autophagy in cells with accumulated mutant tau, α-synuclein, or huntingtin. Treatment with Apt-1 restored proteostasis and inhibited cell death in a mouse model of proteinopathy induced by mutant tau(P301S). We conclude that pharmacological targeting of TRADD may represent a promising strategy for inhibiting cell death and restoring homeostasis to treat human diseases.

PubMed

Microtubule stabilizing drugs-neurodegenerative disease and SCI - #2

A dynamic view of the proteomic landscape during differentiation of ReNcell VM cells, an immortalized human neural progenitor line.

Song Y, Subramanian K, Berberich MJ, Rodriguez S, Latorre IJ, Luria CM, Everley R, Albers MW, Mitchison TJ, Sorger PK.

Abstract: The immortalized human ReNcell VM cell line represents a reproducible and easy-to-propagate cell culture system for studying the differentiation of neural progenitors. To better characterize the starting line and its subsequent differentiation, we assessed protein and phospho-protein levels and cell morphology over a 15-day period during which ReNcell progenitors differentiated into neurons, astrocytes and oligodendrocytes. Five of the resulting datasets measured protein levels or states of phosphorylation based on tandem-mass-tag (TMT) mass spectrometry and four datasets characterized cellular phenotypes using high-content microscopy. Proteomic analysis revealed reproducible changes in pathways responsible for cytoskeletal rearrangement, cell phase transitions, neuronal migration, glial differentiation, neurotrophic signalling and extracellular matrix regulation. Proteomic and imaging data revealed accelerated differentiation in cells treated with the poly-selective CDK and GSK3 inhibitor kenpaullone or the HMG-CoA reductase inhibitor mevastatin, both of which have previously been reported to promote neural differentiation. These data provide in-depth information on the ReNcell progenitor state and on neural differentiation in the presence and absence of drugs, setting the stage for functional studies.

PubMed

Isoguvacine and benzodiazepine derivatives for the treatment of tactile hypersensitivity and anxiety in ASD

Targeting Peripheral Somatosensory Neurons to Improve Tactile-Related Phenotypes in ASD Models.

Orefice LL, Mosko JR, Morency DT, Wells MF, Tasnim A, Mozeika SM, Ye M, Chirila AM, Emanuel AJ, Rankin G, Fame RM, Lehtinen MK, Feng G, Ginty DD.

Abstract: Somatosensory over-reactivity is common among patients with autism spectrum disorders (ASDs) and is hypothesized to contribute to core ASD behaviors. However, effective treatments for sensory over-reactivity and ASDs are lacking. We found distinct somatosensory neuron pathophysiological mechanisms underlie tactile abnormalities in different ASD mouse models and contribute to some ASD-related behaviors. Developmental loss of ASD-associated genes Shank3 or Mecp2 in peripheral mechanosensory neurons leads to region-specific brain abnormalities, revealing links between developmental somatosensory over-reactivity and the genesis of aberrant behaviors. Moreover, acute treatment with a peripherally restricted GABAA receptor agonist that acts directly on mechanosensory neurons reduced tactile over-reactivity in six distinct ASD models. Chronic treatment of Mecp2 and Shank3 mutant mice improved body condition, some brain abnormalities, anxiety-like behaviors, and some social impairments but not memory impairments, motor deficits, or overgrooming. Our findings reveal a potential therapeutic strategy targeting peripheral mechanosensory neurons to treat tactile over-reactivity and select ASD-related behaviors.

PubMed

Targeted protein degradation as a strategy for potent antivirals

Small molecule degraders of the hepatitis C virus protease reduce susceptibility to resistance mutations.

de Wispelaere M, Du G, Donovan KA, Zhang T, Eleuteri NA, Yuan JC, Kalabathula J, Nowak RP, Fischer ES, Gray NS, Yang PL.

Abstract: Targeted protein degradation is a promising drug development paradigm. Here we leverage this strategy to develop a new class of small molecule antivirals that induce proteasomal degradation of viral proteins. Telaprevir, a reversible-covalent inhibitor that binds to the hepatitis C virus (HCV) protease active site is conjugated to ligands that recruit the CRL4CRBN ligase complex, yielding compounds that can both inhibit and induce the degradation of the HCV NS3/4A protease. An optimized degrader, DGY-08-097, potently inhibits HCV in a cellular infection model, and we demonstrate that protein degradation contributes to its antiviral activity. Finally, we show that this new class of antiviral agents can overcome viral variants that confer resistance to traditional enzymatic inhibitors such as telaprevir. Overall, our work provides proof-of-concept that targeted protein degradation may provide a new paradigm for the development of antivirals with superior resistance profiles.

PubMed

Microtubule stabilizing drugs-neurodegenerative disease and SCI - #1

Site occupancy calibration of taxane pharmacology in live cells and tissues.

Pineda JJ, Miller MA, Song Y, Kuhn H, Mikula H, Tallapragada N, Weissleder R, Mitchison TJ.

Abstract: Drug receptor site occupancy is a central pharmacology parameter that quantitatively relates the biochemistry of drug binding to the biology of drug action. Taxanes and epothilones bind to overlapping sites in microtubules (MTs) and stabilize them. They are used to treat cancer and are under investigation for neurodegeneration. In cells, they cause concentration-dependent inhibition of MT dynamics and perturbation of mitosis, but the degree of site occupancy required to trigger different effects has not been measured. We report a live cell assay for taxane-site occupancy, and relationships between site occupancy and biological effects across four drugs and two cell lines. By normalizing to site occupancy, we were able to quantitatively compare drug activities and cell sensitivities independent of differences in drug affinity and uptake/efflux kinetics. Across all drugs and cells tested, we found that inhibition of MT dynamics, postmitotic micronucleation, and mitotic arrest required successively higher site occupancy. We also found interesting differences between cells and drugs, for example, insensitivity of the spindle assembly checkpoint to site occupancy. By extending our assay to a mouse xenograft tumor model, we estimated the initial site occupancy required for paclitaxel to completely prevent tumor growth as 80%. The most important cellular action of taxanes for cancer treatment may be formation of micronuclei, which occurs over a broad range of site occupancies.

PubMed