Exploration of Tetrahydroisoquinoline- and Benzo[c]azepine-Based Sphingosine 1-Phosphate Receptor 1 Agonists for the Treatment of Multiple Sclerosis.

Because of the wide use of Fingolimod for the treatment of multiple sclerosis (MS) and its cardiovascular side effects such as bradycardia, second-generation sphingosine 1-phosphate receptor 1 (S1P1) agonist drugs for MS have been developed and approved by FDA. The issue of bradycardia is still present with the new drugs, however, which necessitates further exploration of S1P1 agonists with improved safety profiles for next-generation MS drugs. Herein, we report a tetrahydroisoquinoline or a benzo[c]azepine core-based S1P1 agonists such as 32 and 60 after systematic examination of hydrophilic groups and cores. We investigated the binding modes of our representative compounds and their molecular interactions with S1P1 employing recent S1P1 cryo-EM structures. Also, favorable ADME properties of our compounds were shown. Furthermore, in vivo efficacy of our compounds was clearly demonstrated with PLC and EAE studies. Also, the preliminary in vitro cardiovascular safety of our compound was verified with human iPSC-derived cardiomyocytes.

Levosimendan inhibits disulfide tau oligomerization and ameliorates tau pathology in TauP301L-BiFC mice.

Tau oligomers play critical roles in tau pathology and are responsible for neuronal cell death and transmitting the disease in the brain. Accordingly, preventing tau oligomerization has become an important therapeutic strategy to treat tauopathies, including Alzheimer's disease. However, progress has been slow because detecting tau oligomers in the cellular context is difficult. Working toward tau-targeted drug discovery, our group has developed a tau-BiFC platform to monitor and quantify tau oligomerization. By using the tau-BiFC platform, we screened libraries with FDA-approved and passed phase I drugs and identified levosimendan as a potent anti-tau agent that inhibits tau oligomerization. 14C-isotope labeling of levosimendan revealed that levosimendan covalently bound to tau cysteines, directly inhibiting disulfide-linked tau oligomerization. In addition, levosimendan disassembles tau oligomers into monomers, rescuing neurons from aggregation states. In comparison, the well-known anti-tau agents methylene blue and LMTM failed to protect neurons from tau-mediated toxicity, generating high-molecular-weight tau oligomers. Levosimendan displayed robust potency against tau oligomerization and rescued cognitive declines induced by tauopathy in the TauP301L-BiFC mouse model. Our data present the potential of levosimendan as a disease-modifying drug for tauopathies.

Erratum to: Human umbilical cord mesenchymal stem cell-derived mitochondria (PN-101) attenuate LPS-induced inflammatory responses by inhibiting NFκB signaling pathway.

[Erratum to: BMB Reports 2022; 55(3): 136-141, PMID: 34488927, PMCID: PMC8972135] The BMB Reports would like to correct in BMB Rep. 55(3):136-141, titled "Human umbilical cord mesenchymal stem cell-derived mitochondria (PN-101) attenuate LPS-induced inflammatory responses by inhibiting NFκB signaling pathway". This research was supported by NRF-2016R1A2B4007640 grant (to C-H Kim). Since grant number is incorrect, this information has now been corrected as follows: We would like to thank various Paean Biotechnology Inc. members who participated in the project. This work was supported by NRF-2018M3A9B5023055 grant (to C-H Kim). The authors apologize for any inconvenience or confusion that may be caused by this error. The ACKNOWLEDGEMENTS of Original PDF version have been corrected.

Human umbilical cord mesenchymal stem cell-derived mitochondria (PN-101) attenuate LPS-induced inflammatory responses by inhibiting NFκB signaling pathway.

Inflammation is one of the body's natural responses to injury and illness as part of the healing process. However, persistent inflammation can lead to chronic inflammatory diseases and multi-organ failure. Altered mitochondrial function has been implicated in several acute and chronic inflammatory diseases by inducing an abnormal inflammatory response. Therefore, treating inflammatory diseases by recovering mitochondrial function may be a potential therapeutic approach. Recently, mitochondrial transplantation has been proven to be beneficial in hyperinflammatory animal models. However, it is unclear how mitochondrial transplantation attenuates inflammatory responses induced by external stimuli. Here, we isolated mitochondria from umbilical cord-derived mesenchymal stem cells, referred as to PN-101. We found that PN-101 could significantly reduce LPS-induced mortality in mice. In addition, in phorbol 12-myristate 13-acetate (PMA)-treated THP-1 macrophages, PN-101 attenuated LPS-induced increase production of pro-inflammatory cytokines. Furthermore, the anti-inflammatory effect of PN-101 was mediated by blockade of phosphorylation, nuclear translocation, and trans-activity of NFκB. Taken together, our results demonstrate that PN-101 has therapeutic potential to attenuate pathological inflammatory responses. [BMB Reports 2022; 55(3): 136-141].

Pharmacophore-Based Virtual Screening of Novel Competitive Inhibitors of the Neurodegenerative Disease Target Kynurenine-3-Monooxygenase.

The pathogenesis of several neurodegenerative diseases such as Alzheimer's or Huntington's disease has been associated with metabolic dysfunctions caused by imbalances in the brain and cerebral spinal fluid levels of neuroactive metabolites. Kynurenine monooxygenase (KMO) is considered an ideal therapeutic target for the regulation of neuroactive tryptophan metabolites. Despite significant efforts, the known KMO inhibitors lack blood-brain barrier (BBB) permeability and upon the mimicking of the substrate binding mode, are subject to produce reactive oxygen species as a side reaction. The computational drug design is further complicated by the absence of complete crystal structure information for human KMO (hKMO). In the current work, we performed virtual screening of readily available compounds using several protein-ligand complex pharmacophores. Each of the pharmacophores accounts for one of three distinct reported KMO protein-inhibitor binding conformations. As a result, six novel KMO inhibitors were discovered based on an in vitro fluorescence assay. Compounds VS1 and VS6 were predicted to be BBB permeable and avoid the hydrogen peroxide production dilemma, making them valuable, novel hit compounds for further drug property optimization and advancement in the drug design pipeline.

CHIP-mediated hyperubiquitylation of tau promotes its self-assembly into the insoluble tau filaments.

The tau protein is a highly soluble and natively unfolded protein. Under pathological conditions, tau undergoes multiple post-translational modifications (PTMs) and conformational changes to form insoluble filaments, which are the proteinaceous signatures of tauopathies. To dissect the crosstalk among tau PTMs during the aggregation process, we phosphorylated and ubiquitylated recombinant tau in vitro using GSK3ß and CHIP, respectively. The resulting phospho-ub-tau contained conventional polyubiquitin chains with lysine 48 linkages, sufficient for proteasomal degradation, whereas unphosphorylated ub-tau species retained only one-three ubiquitin moieties. Mass-spectrometric analysis of in vitro reconstituted phospho-ub-tau revealed seven additional ubiquitylation sites, some of which are known to stabilize tau protofilament stacking in the human brain with tauopathy. When the ubiquitylation reaction was prolonged, phospho-ub-tau transformed into insoluble hyperubiquitylated tau species featuring fibrillar morphology and in vitro seeding activity. We developed a small-molecule inhibitor of CHIP through biophysical screening; this effectively suppressed tau ubiquitylation in vitro and delayed its aggregation in cultured cells including primary cultured neurons. Our biochemical findings point to a "multiple-hit model," where sequential events of tau phosphorylation and hyperubiquitylation function as a key driver of the fibrillization process, thus indicating that targeting tau ubiquitylation may be an effective strategy to alleviate the course of tauopathies.

Aggresomal sequestration and STUB1-mediated ubiquitylation during mammalian proteaphagy of inhibited proteasomes.

The 26S proteasome, a self-compartmentalized protease complex, plays a crucial role in protein quality control. Multiple levels of regulatory systems modulate proteasomal activity for substrate hydrolysis. However, the destruction mechanism of mammalian proteasomes is poorly understood. We found that inhibited proteasomes are sequestered into the insoluble aggresome via HDAC6- and dynein-mediated transport. These proteasomes colocalized with the autophagic receptor SQSTM1 and cleared through selective macroautophagy, linking aggresomal segregation to autophagic degradation. This proteaphagic pathway was counterbalanced with the recovery of proteasomal activity and was critical for reducing cellular proteasomal stress. Changes in associated proteins and polyubiquitylation on inhibited 26S proteasomes participated in the targeting mechanism to the aggresome and autophagosome. The STUB1 E3 Ub ligase specifically ubiquitylated purified human proteasomes in vitro, mainly via Lys63-linked chains. Genetic and chemical inhibition of STUB1 activity significantly impaired proteasome processing and reduced resistance to proteasomal stress. These data demonstrate that aggresomal sequestration is the crucial upstream event for proteasome quality control and overall protein homeostasis in mammals.

New Surface Modification Method To Develop a PET-Based Membrane with Enhanced Ion Permeability and Organic Fouling Resistance for Efficient Production of Marine Microalgae.

This paper presents a new surface modification strategy to develop a poly(ethylene terephthalate) (PET)-based membrane having a hydrophilic surface, high nutrient ion permeability, sufficient mechanical strength, and organic fouling resistance, using an anthracene (ANT)-attached polyethylene glycol (PEG) surface modification agent (SMA) synthesized in this work. During the modification process, the ANT parts of the SMAs poke through and anchor to the surface of a commercial PET woven fabric via physical interactions and mechanical locking. The PEG chain parts coat the surface in the brush and arch forms, which generates a hydration layer on the fabric surface. The consequently obtained surface property and unique structure of the modified PET-based membrane result in higher nitrate ion permeability, organic fouling resistance, and microalgae production compared to those of the unmodified one. These are also affected by the molecular weight of the PEG and the number density of the anchored SMAs. The study demonstrates that this new surface modification method has the potential to allow the development of a desirable PET-based membrane for the efficient massive production of marine microalgae.

Nrf2 activator via interference of Nrf2-Keap1 interaction has antioxidant and anti-inflammatory properties in Parkinson's disease animal model.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by abnormal movement, including slowed movements, shuffling gait, lack of balance, and tremor. Oxidative stress has been shown to play a decisive role in dopaminergic neuronal cell death in PD. The nuclear factor E2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) signaling pathway provides the main defense system against oxidative stress by inducing the expression of antioxidant enzyme genes. Direct interference in the Keap1-Nrf2 protein-protein interaction (PPI) has emerged as an effective strategy for Nrf2 activation. Therefore, we searched for novel Nrf2 activators that can disrupt Nrf2-Keap1 interaction by using a virtual screening approach and identified a potent Nrf2 activator, KKPA4026. KKPA4026 was confirmed to induce the expression of the Nrf2-dependent antioxidant enzymes heme oxygenase-1, glutamate-cysteine ligase catalytic subunit, glutamate-cysteine ligase regulatory subunit, and NAD(P)H:quinone oxidoreductase 1 in BV-2 cells. Furthermore, KKPA4026 showed anti-inflammatory effects in an Nrf2-dependent manner. In a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD, KKPA4026 effectively attenuated PD-associated behavioral deficits and protected dopaminergic neurons. In summary, we identified KKPA4026 as a novel Nrf2 activator and suggested that Nrf2 activation through interference with the Nrf2-Keap1 interaction may be effective for PD treatment.

Evaluation of anti-depressant effects of phthalazinone-based triple-acting small molecules against 5-HT2A, 5-HT2C, and the serotonin transporter.

Development of highly effective, safe, and fast-acting anti-depressants is urgently required for the treatment of major depressive disorder. It has been suggested that targeting 5-HT2A and 5-HT2C in addition to inhibition of serotonin reuptake may be beneficial in generating anti-depressant agents with better pharmacology and less adverse effects. We have developed phthalazinone-based compounds that potently bind to 5-HT2A, 5-HT2C, and the serotonin transporter. The representative compounds 11j and 11l displayed strong binding affinities against these targets, and showed favorable toxicity profiles as determined by hERG binding and CYP inhibition assays. Furthermore, these compounds presented promising anti-depressant effects comparable to fluoxetine and also synergistic effects with fluoxetine in forced swimming test, which implicates these compounds can be developed to help the treatment of major depressive disorder.

Metabolic engineering of Escherichia coli to produce a monophosphoryl lipid A adjuvant.

Monophosphoryl lipid A (MPLA) species, including MPL (a trade name of GlaxoSmithKline) and GLA (a trade name of Immune Design, a subsidiary of Merck), are widely used as an adjuvant in vaccines, allergy drugs, and immunotherapy to boost the immune response. Even though MPLA is a derivative of lipopolysaccharide (LPS), a component of the outer membrane of Gram-negative bacteria, bacterial strains producing MPLA have not been found in nature nor engineered. In fact, MPLA generation involves expensive and laborious procedures based on synthetic routes or chemical transformation of precursors isolated from Gram-negative bacteria. Here, we report the engineering of an Escherichia coli strain for in situ production and accumulation of MPLA. Furthermore, we establish a succinct method for purifying MPLA from the engineered E. coli strain. We show that the purified MPLA (named EcML) stimulates the mouse immune system to generate antigen-specific IgG antibodies similarly to commercially available MPLA, but with a dramatically reduced manufacturing time and cost. Our system, employing the first engineered E. coli strain that directly produces the adjuvant EcML, could transform the current standard of industrial MPLA production.

Investigation of Molecular Details of Keap1-Nrf2 Inhibitors Using Molecular Dynamics and Umbrella Sampling Techniques.

In this study, we investigate the atomistic details of Keap1-Nrf2 inhibitors by in-depth modeling techniques, including molecular dynamics (MD) simulations, and the path-based free energy method of umbrella sampling (US). The protein-protein interaction (PPI) of Keap1-Nrf2 is implicated in several neurodegenerative diseases like cancer, diabetes, and cardiomyopathy. A better understanding of the five sub-pocket binding sites for Nrf2 (ETGE and DLG motifs) inside the Kelch domain would expedite the inhibitor design process. We selected four protein-ligand complexes with distinct co-crystal ligands and binding occupancies inside the Nrf2 binding site. We performed 100 ns of MD simulation for each complex and analyzed the trajectories. From the results, it is evident that one ligand (1VV) has flipped inside the binding pocket, whereas the remaining three were stable. We found that Coulombic (Arg483, Arg415, Ser363, Ser508, and Ser602) and Lennard-Jones (Tyr525, Tyr334, and Tyr572) interactions played a significant role in complex stability. The obtained binding free energy values from US simulations were consistent with the potencies of simulated ligands. US simulation highlight the importance of basic and aromatic residues in the binding pocket. A detailed description of the dissociation process brings valuable insight into the interaction of the four selected protein-ligand complexes, which could help in the future to design more potent PPI inhibitors.

Structural hybridization of pyrrolidine-based T-type calcium channel inhibitors and exploration of their analgesic effects in a neuropathic pain model.

Highly effective and safe drugs for the treatment of neuropathic pain are urgently required and it was shown that blocking T-type calcium channels can be a promising strategy for drug development for neuropathic pain. We have developed pyrrolidine-based T-type calcium channel inhibitors by structural hybridization and subsequent assessment of in vitro activities against Cav3.1 and Cav3.2 channels. Profiling of in vitro ADME properties of compounds was also carried out. The representative compound 17h showed comparable in vivo efficacy to gabapentin in the SNL model, which indicates T-type calcium channel inhibitors can be developed as effective therapeutics for neuropathic pain.

Synthesis and biological evaluation of pyrrolidine-based T-type calcium channel inhibitors for the treatment of neuropathic pain.

The treatment of neuropathic pain is one of the urgent unmet medical needs and T-type calcium channels are promising therapeutic targets for neuropathic pain. Several potent T-type channel inhibitors showed promising in vivo efficacy in neuropathic pain animal models and are being investigated in clinical trials. Herein we report development of novel pyrrolidine-based T-type calcium channel inhibitors by pharmacophore mapping and structural hybridisation followed by evaluation of their Cav3.1 and Cav3.2 channel inhibitory activities. Among potent inhibitors against both Cav3.1 and Cav3.2 channels, a promising compound 20n based on in vitro ADME properties displayed satisfactory plasma and brain exposure in rats according to in vivo pharmacokinetic studies. We further demonstrated that 20n effectively improved the symptoms of neuropathic pain in both SNL and STZ neuropathic pain animal models, suggesting modulation of T-type calcium channels can be a promising therapeutic strategy for the treatment of neuropathic pain.

Identification of crizotinib derivatives as potent SHIP2 inhibitors for the treatment of Alzheimer's disease.

SH2 domain-containing inositol 5'-phosphatase 2 (SHIP2) is a lipid phosphatase that produce phosphatidylinositol 3,4-bisphosphate (PI(3,4)P2) from phosphatidylinositol 3,4,5-triphosphate (PI(3,4,5)P3), and is involved in many diseases such as neurodegenerative diseases. A recent report demonstrating that SHIP2 inhibition decreased tau hyperphosphorylation induced by amyloid ß and rescued memory impairment in a transgenic Alzheimer's disease mouse model indicates SHIP2 can be a promising therapeutic target for Alzheimer's disease. In the present study, we have developed novel, potent SHIP2 inhibitors by extensive structural elaboration of crizotinib discovered from a high-throughput screening. Our representative compound 43 potently inhibited SHIP2 activity as well as GSK3ß activation in HT22 neuronal cells. It was also shown that 43 has favorable physicochemical properties, especially high brain penetration. Considering SHIP2 is one of key signal mediators for tau hyperphosphorylation, our potent SHIP2 inhibitor 43 may function as a promising lead compound for the treatment of Alzheimer's disease.

GRP78-targeted in-silico virtual screening of novel anticancer agents.

Overexpression of GRP78 in a variety of cancers such as glioblastoma, leukemia, lung, prostate, breast, gastric, and colon makes it a prime target for anticancer drug development. Present study reports GRP78-based design of novel anticancer agents using in-silico methods. As a first step toward the work, the interactions between GRP78 and 15 known ligands were modeled by docking simulation. The docked complex, GRP78-13, superior to other compounds with respect to its experimental activity and energy descriptors, was deduced into a structure-based pharmacophore. This hypothesis was applied as a screening filter to Asinex and Chemdiv databases. Finally, 23 hits were tested in vitro. Among these, VH1019 and VH1011 induced a concentration-dependent strong broad antiproliferative effect in glioma (U87-MG), breast cancer (MCF-7), and prostate cancer (DU-145) cell lines as compared to nontumorigenic control, neonatal foreskin fibroblast (HFF-1). These compounds showed preferential growth inhibition of cancer cells over normal cells. The acetohydrazide derivative VH1019 was identified as a potential new chemotype for GRP78 inhibitors with an IC50 of 12.7 µM in MCF-7.

Enzyme/whole-cell biotransformation of plant oils, yeast derived oils, and microalgae fatty acid methyl esters into n-nonanoic acid, 9-hydroxynonanoic acid, and 1,9-nonanedioic acid.

Oils and fatty acids are important renewable resources provided by nature. Therefore, biotransformation of renewable oils and fatty acids into industrially relevant C9 chemicals was investigated in this study. Olive oil, soybean oil, yeast derived oil, and microalgae fatty acid methyl esters were converted into n-nonanoic acid, 9-hydroxynonanoic acid, and 1,9-nonanedioic acid by a lipase and a recombinant Escherichia coli expressing oleate hydratase, long chain secondary alcohol dehydrogenase, Baeyer-Villiger monooxygenase, long chain primary alcohol dehydrogenase, and aldehyde dehydrogenase. It was found that n-nonanoic acid and azelaic acid could be produced to a concentration of 4.3 mM from 3 g/L olive oil with a specific product formation rate of 3.1 U/g dry cells. Biotransformation rates were influenced by compositions of fatty acids and purity of the starting material. This study may contribute to the production of industrially relevant C9 chemicals from renewable oils and fatty acids by simultaneous enzyme/whole-cell biotransformation.

Ligand-controlled Regiodivergent C-H Alkenylation of Pyrazoles and its Application to the Synthesis of Indazoles.

Regioselective C4-, C5-, and di-alkenylations of pyrazoles were achieved. An electrophilic Pd catalyst generated by trifluoroacetic acid (TFA) and 4,5-diazafluoren-9-one (DAF) leads to C4-alkenylation, whereas KOAc and mono-protected amino acid (MPAA) ligand Ac-Val-OH give C5-alkenylation. A combination of palladium acetate, silver carbonate, and pivalic acid affords dialkenylation products. Annulation through sequential alkenylation, thermal 6π-electrocyclization, and oxidation gives functionalized indazoles. This comprehensive strategy greatly expands the range of readily accessible pyrazole and indazole derivatives, enabling useful regiodivergent C-H functionalization of pyrazoles and other heteroaromatic systems.