Crowdsourced identification of multi-target kinase inhibitors for RET- and TAU- based disease: The Multi-Targeting Drug DREAM Challenge

A continuing challenge in modern medicine is the identification of safer and more efficacious drugs. Precision therapeutics, which have one molecular target, have been long promised to be safer and more effective than traditional therapies. This approach has proven to be challenging for multiple reasons including lack of efficacy, rapidly acquired drug resistance, and narrow patient eligibility criteria. An alternative approach is the development of drugs that address the overall disease network by targeting multiple biological targets (‘polypharmacology’). Rational development of these molecules will require improved methods for predicting single chemical structures that target multiple drug targets. To address this need, we developed the Multi-Targeting Drug DREAM Challenge, in which we challenged participants to predict single chemical entities that target pro-targets but avoid anti-targets for two unrelated diseases: RET-based tumors and a common form of inherited Tauopathy. Here, we report the results of this DREAM Challenge and the development of two neural network-based machine learning approaches that were applied to the challenge of rational polypharmacology. Together, these platforms provide a potentially useful first step towards developing lead therapeutic compounds that address disease complexity through rational polypharmacology.     

Superoxide Dismutase Activity and Lipid Peroxidation in the Liver of Guinea Pig Infected with Leptospira interrogans

Superoxide dismutase (SOD) activity and the degree of lipid peroxidation were studied over a two week period in guinea pigs infected with Leptospira interrogans derived from wild mice. The total SOD activity in infected host liver increased by four-fold two days after infection; this was followed by a 20% decrease resulting in levels comparable to normal, uninfected liver. During the period of decreasing SOD activity after day two, the levels of TBA-reactive material (TBARS) are increased by three-fold in infected guinea pig, liver, compared to uninfected liver. The results indicate that SOD attenuates intracellular superoxide-mediated toxic effects in guinea pigs infected with L. interrogans. In addition, electron microscopy structure demonstrates correlated pathogenic shrinkage of mitochondrial and Kupffer cell structures.     

Bax inhibitor-1 enhances survival and neuronal differentiation of embryonic stem cells via differential regulation of mitogen-activated protein kinases activities

Bax inhibitor-1 (BI-1), a member of the BI-1 family of integral membrane proteins, was originally identified as an inhibitor of stress-induced cell death in mammalian cells. Previous studies have shown that the withdrawal of leukemia inhibitory factor (LIF) results in differentiation of the majority of mouse embryonic stem (mES) cells into various cell lineages, while some ES cells die within 3days. Thus, to investigate the function of BI-1 in ES cell survival and neuronal differentiation, we generated mES cell lines that overexpress BI-1 or a carboxy-terminal BI-1ΔC mutant. Overexpression of BI-1 in mES cells significantly increased cell viability and resistance to apoptosis induced by LIF withdrawal, while the control vector or BI-1ΔC-overexpressing mES cells had no effect. Moreover, overexpression of BI-1 produced significant inhibition of the p38 mitogen-activated protein kinases (MAPK) pathway in response to LIF withdrawal, while activity of the extracellular signal-regulated kinase (ERK)/c-Jun N-terminal kinase (JNK) MAPK pathway was increased. Interestingly, we found that BI-1-overexpressing cells showed higher expression levels of neuroectodermal markers (Otx1, Lmx1b, En1, Pax2, Wnt1, Sox1, and Nestin) and greater neuronal differentiation efficiency than control or BI-1ΔC-overexpressing mES cells did. Considering these findings, our results indicated that BI-1-modulated MAPK activity plays a key role in protecting mES cells from LIF-withdrawal-induced apoptosis and in promoting their differentiation toward neuronal lineages.     

Investigating the effects of positive charge and hydrophobicity on the cell selectivity, mechanism of action and anti-inflammatory activity of a Trp-rich antimicrobial peptide indolicidin

To investigate the effects of positive charge and hydrophobicity on the cell selectivity, mechanism of action and anti-inflammatory activity of a Trp-rich antimicrobial peptide indolicidin (IN), a series of IN analogs with Trp→Lys substitution were synthesized. All IN analogs displayed an approximately 7- to 18-fold higher cell selectivity, compared with IN. IN, IN-1 and IN-2 depolarized (50−90%) the cytoplasmic membrane potential of Staphylococcus aureus close to minimal inhibitory concentration (5–10 μg mL⁻¹). However, other IN analogs (IN-3 and IN-4) displayed very low ability in membrane depolarization even at 40 μg mL⁻¹. Confocal laser-scanning microscopy revealed that IN-3 and IN-4 penetrated the Escherichia coli cell membrane, whereas IN, IN-1 and IN-2 did not enter the cell membrane. In the gel retardation assay, IN-3 and IN-4 bound more strongly to DNA compared with IN, IN-1 and IN-2. These findings suggest that the mechanism of antimicrobial action of IN-3 and IN-4 may be involved in the inhibition of intracellular functions via interference with DNA/RNA synthesis. Unlike IN, all IN analogs did not inhibit nitric oxide production or inducible nitric oxide synthase mRNA expression in lipopolysaccharide-stimulated mouse macrophage RAW264.7 cells, indicating that the hydrophobicity of IN is more important for anti-inflammatory activity in lipopolysaccharide-treated macrophage cells than the positive charge.     

Strongyloides myopotami (Secernentea: Strongyloididae) from the Intestine of Feral Nutrias (Myocastor coypus) in Korea

Surveys on helminthic fauna of the nutria, Myocastor coypus, have seldom been performed in the Republic of Korea. In the present study, we describe Strongyloides myopotami (Secernentea: Strongyloididae) recovered from the small intestine of feral nutrias. Total 10 adult nutrias were captured in a wetland area in Gimhae-si (City), Gyeongsangnam-do (Province) in April 2013. They were transported to our laboratory, euthanized with ether, and necropsied. About 1,300 nematode specimens were recovered from 10 nutrias, and some of them were morphologically observed by light and scanning electron microscopies. They were 3.7-4.7 (4.0±0.36) mm in length, 0.03-0.04 (0.033) mm in width. The worm dimension and other morphological characters, including prominent lips of the vulva, blunted conical tail, straight type of the ovary, and 8-chambered stoma, were all consistent with S. myopotami. This nematode fauna is reported for the first time in Korea.     

Developmental competence of IVM pig oocytes after SCNT in relation to the shrinkage pattern induced by hyperosmotic treatment

The objective of this study was to examine the developmental competence of IVM pig oocytes in relation to the pattern of morphologic changes after exposure to hyperosmotic medium to select oocytes of a higher quality. IVM oocytes were treated with a hyperosmotic (593 mOsm) medium containing NaCl, sorbitol, or sucrose. Oocytes that shrunk spherically (SSP oocytes) or in irregular shapes (SIR oocytes) were collected separately, and washed for 15 minutes in an isotonic (297 mOsm) medium for recovery. Irrespective of the chemicals used, hyperosmotic treatment of oocytes for 1 hour or 15 minutes did not alter embryonic development after parthenogenesis (PA) and SCNT. A significantly higher proportion of SSP oocytes developed to the blastocyst stage (34.0%) compared with SIR oocytes (15.8%) after PA. The intracellular glutathione content was significantly higher in SSP oocytes than in SIR oocytes. Conversely, the reactive oxygen species level was significantly higher in SIR oocytes than in SSP oocytes. The maturation promoting factor level as measured by p34^cdc2 kinase activity was not influenced by hyperosmotic treatment itself but was 1.3-fold higher (P < 0.05) in SSP oocytes than in SIR oocytes. When IVM oocytes were divided into two groups according to their diameters (large and small), and treated separately in hyperosmotic medium, significantly more SSP oocytes (71.4%) were found in the large oocytes than in the small oocytes (51.4%). Moreover, the proportion of metaphase II oocytes was significantly higher in SSP oocytes than in SIR oocytes in both groups (98.5% vs. 73.1% in large oocytes, and 92.2% vs. 48.0% in small oocytes). After SCNT, a significantly higher proportion of SSP oocytes displayed blastocyst formation (36.4%) than untreated (29.0%) and SIR oocytes (22.1%). Our results demonstrated that SSP oocytes were of a higher quality than SIR oocytes, which was shown by higher intracellular glutathione and maturation promoting factor levels, lower reactive oxygen species levels, and improved embryonic development to the blastocyst stage after PA and SCNT.     

βTrCP-mediated ubiquitylation regulates protein stability of Mis18β in a cell cycle-dependent manner

Ubiquitin E3 ligases including SCF complex are key regulators of cell cycle. Here, we show that Mis18β, a component of Mis18 complex governing CENP-A localization, is a new substrate of βTrCP-containing SCF complex. βTrCP interacted with Mis18β exclusively during interphase but not during mitosis and mediated proteasomal degradation of Mis18β leading to the inactivation of Mis18 complex during interphase. In addition, uncontrolled stabilization of Mis18β caused cell death. Together, we propose that βTrCP-mediated regulation of Mis18β stability is a mechanism to restrict centromere function of Mis18 complex from late mitosis to early G1 phase.