Publications by authors named "Chi-Hao Luan"

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with no cure, and current treatment options are very limited. Previously, we performed a high-throughput screen to identify small molecules that inhibit protein aggregation caused by a mutation in the gene that encodes superoxide dismutase 1 (SOD1), which is responsible for about 25% of familial ALS. This resulted in three hit series of compounds that were optimized over several years to give three compounds that were highly active in a mutant SOD1 ALS model.

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Major depressive disorder is a critical public health problem with a lifetime prevalence of nearly 17% in the United States. One potential therapeutic target is the interaction between hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and an auxiliary subunit of the channel named tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b). HCN channels regulate neuronal excitability in the mammalian hippocampus, and recent work has established that antagonizing HCN function rescues cognitive impairment caused by chronic stress.

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Mitochondria are biosynthetic, bioenergetic, and signaling organelles with a critical role in cellular physiology. Dysfunctional mitochondria are associated with aging and underlie the cause of a wide range of diseases, from neurodegeneration to cancer. Through signaling, mitochondria regulate diverse biological outcomes.

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The heart is capable of activating protective mechanisms in response to ischemic injury to support myocardial survival and performance. These mechanisms have been recognized primarily in the ischemic heart, involving paracrine signaling processes. Here, we report a distant cardioprotective mechanism involving hepatic cell mobilization to the ischemic myocardium in response to experimental myocardial ischemia-reperfusion (MI-R) injury.

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In many enveloped virus families, including HIV and HSV, a crucial, yet unexploited, step in the viral life cycle is releasing particles from the infected cell membranes. This release process is mediated by host ESCRT complex proteins, which are recruited by viral structural proteins and provides the mechanical means for membrane scission and subsequent viral budding. The prazole drug, tenatoprazole, was previously shown to bind to ESCRT complex member Tsg101 and to quantitatively block the release of infectious HIV-1 from cells in culture.

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Prion-like protein aggregation underlies the pathology of a group of fatal neurodegenerative diseases in humans, including Alzheimer's disease (AD), Parkinson's disease, amyotrophic lateral sclerosis, and transmissible spongiform encephalopathy. At present, few high-throughput screening (HTS) systems are available for anti-prion small-molecule identification. Here we describe an innovative phenotypic HTS system in yeast that allows for efficient identification of chemical compounds that eliminate the yeast prion [SWI].

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Enzymes in the methylerythritol phosphate pathway make attractive targets for antibacterial activity due to their importance in isoprenoid biosynthesis and the absence of the pathway in mammals. The fifth enzyme in the pathway, 2-C-methyl-d-erythritol-2,4-cyclodiphosphate synthase (IspF), contains a catalytically important zinc ion in the active site. A series of de novo designed compounds containing a zinc binding group was synthesized and evaluated for antibacterial activity and interaction with IspF from Burkholderia pseudomallei, the causative agent of Whitmore's disease.

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Article Synopsis
  • Autotransporters are a major group of proteins in Gram-negative bacteria, primarily involved in helping these bacteria attach to host surfaces.
  • The study details the structure of UpaB, a specific autotransporter found in uropathogenic E. coli, and shows its ability to interact with important host molecules, glycosaminoglycans, and fibronectin.
  • The research uncovers unexpected diversity in the structure of autotransporters, suggesting they may have more complex roles in bacterial interactions with hosts during infections.
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Despite its long history, until now, no receptor has been identified for aspirin, one of the most widely used medicines worldwide. Here we report that peroxisome proliferator-activated receptor alpha (PPARα), a nuclear hormone receptor involved in fatty acid metabolism, serves as a receptor of aspirin. Detailed proteomic analyses including cheminformatics, thermal shift assays, and TR-FRET revealed that aspirin, but not other structural homologs, acts as a PPARα ligand through direct binding at the Tyr314 residue of the PPARα ligand-binding domain.

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Induction of TLR2 activation depends on its association with the adapter protein MyD88. We have found that TLR2 and MyD88 levels are elevated in the hippocampus and cortex of patients with Alzheimer's disease (AD) and in a 5XFAD mouse model of AD. Since there is no specific inhibitor of TLR2, to target induced TLR2 from a therapeutic angle, we engineered a peptide corresponding to the TLR2-interacting domain of MyD88 (TIDM) that binds to the BB loop of only TLR2, and not other TLRs.

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HIV-1 replication requires Tsg101, a component of cellular endosomal sorting complex required for transport (ESCRT) machinery. Tsg101 possesses an ubiquitin (Ub) E2 variant (UEV) domain with a pocket that can bind PT/SAP motifs and another pocket that can bind Ub. The PTAP motif in the viral structural precursor polyprotein, Gag, allows the recruitment of Tsg101 and other ESCRTs to virus assembly sites where they mediate budding.

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Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are expressed ubiquitously throughout the brain, where they function to regulate the excitability of neurons. The subcellular distribution of these channels in pyramidal neurons of hippocampal area CA1 is regulated by tetratricopeptide repeat-containing Rab8b interacting protein (TRIP8b), an auxiliary subunit. Genetic knockout of HCN pore forming subunits or TRIP8b, both lead to an increase in antidepressant-like behavior, suggesting that limiting the function of HCN channels may be useful as a treatment for Major Depressive Disorder (MDD).

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Peroxisome proliferator-activated receptor-α (PPARα) regulates hepatic fatty acid catabolism and mediates the metabolic response to starvation. Recently we found that PPARα is constitutively activated in nuclei of hippocampal neurons and controls plasticity via direct transcriptional activation of CREB. Here we report the discovery of three endogenous PPARα ligands-3-hydroxy-(2,2)-dimethyl butyrate, hexadecanamide, and 9-octadecenamide-in mouse brain hippocampus.

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Unlabelled: Mycobacterium tuberculosis is a human respiratory pathogen that causes the deadly disease tuberculosis. The rapid global spread of antibiotic-resistant M. tuberculosis makes tuberculosis infections difficult to treat.

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The fluorescence-based thermal shift (FTS) data presented here include Table S1 and Fig. S1, and are supplemental to our original research article describing detailed structural, FTS, and fluorescence polarization analyses of the Salmonella enterica subsp. entrica serovar Typhimurium str.

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Most low GC Gram-positive bacteria possess an essential walKR two-component system (TCS) for signal transduction involved in regulating cell wall homoeostasis. Despite the well-established intracellular regulatory mechanism, the role of this TCS in extracellular signal recognition and factors that modulate the activity of this TCS remain largely unknown. Here we identify the extracellular receptor of the kinase 'WalK' (erWalK) as a key hub for bridging extracellular signal input and intracellular kinase activity modulation in Staphylococcus aureus.

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Multidrug transcription regulator AcrR from Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 belongs to the tetracycline repressor family, one of the largest groups of bacterial transcription factors.

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Long-distance intracellular transport of organelles, mRNA, and proteins ("cargo") occurs along the microtubule cytoskeleton by the action of kinesin and dynein motor proteins, but the vast network of factors involved in regulating intracellular cargo transport are still unknown. We capitalize on the Drosophila melanogaster S2 model cell system to monitor lysosome transport along microtubule bundles, which require enzymatically active kinesin-1 motor protein for their formation. We use an automated tracking program and a naive Bayesian classifier for the multivariate motility data to analyze 15,683 gene phenotypes and find 98 proteins involved in regulating lysosome motility along microtubules and 48 involved in the formation of microtubule filled processes in S2 cells.

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The bipolar spiral ganglion neurons (SGN) carry sound information from cochlear hair cells to the brain. After noise, antibiotic or toxic insult to the cochlea, damage to SGN and/or hair cells causes hearing impairment. Damage ranges from fiber and synapse degeneration to dysfunction and loss of cells.

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Neurotrophins are important for neuronal health and function. Here, statins, inhibitors of HMG-CoA reductase and cholesterol lowering drugs, were found to stimulate expression of neurotrophins in brain cells independent of the mevalonate pathway. Time-resolved fluorescence resonance energy transfer (FRET) analyses, computer-derived simulation, site-directed mutagenesis, thermal shift assay, and de novo binding followed by electrospray ionization tandem mass spectrometry (ESI-MS) demonstrates that statins serve as ligands of PPARα and that Leu331 and Tyr 334 residues of PPARα are important for statin binding.

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Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels function in the brain to limit neuronal excitability. Limiting the activity of these channels has been proposed as a therapy for major depressive disorder, but the critical role of HCN channels in cardiac pacemaking has limited efforts to develop therapies directed at the channel. Previous studies indicated that the function of HCN is tightly regulated by its auxiliary subunit, tetratricopeptide repeat-containing Rab8b interacting protein (TRIP8b), which is not expressed in the heart.

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Despite their value as sources of therapeutic drug targets, membrane proteomes are largely inaccessible to high-throughput screening (HTS) tools designed for soluble proteins. An important example comprises the membrane proteins that bind amyloid β oligomers (AβOs). AβOs are neurotoxic ligands thought to instigate the synapse damage that leads to Alzheimer's dementia.

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The fluorescence thermal shift (FTS) method is a biophysical technique that can improve productivity in a structural genomics pipeline and provide a fast and easy platform for identifying ligands in protein function or drug discovery screening. The technique has gained widespread popularity in recent years due to its broad-scale applicability, throughput, and functional relevance. FTS is based on the principle that a protein unfolds at a critical temperature that depends upon its intrinsic stability.

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Catenulispora acidiphila is a newly identified lineage of actinomycetes that produces antimicrobial activities and represents a promising source of novel antibiotics and secondary metabolites. Among the discovered protein coding genes, 68 % were assigned a putative function, while the remaining 32 % are genes encoding "hypothetical" proteins. Caci_0382 is one of the "hypothetical" proteins that has very few homologs.

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