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We present compelling evidence for the existence of an evolutionary adaptive response to viral agents such as SARS-CoV-2, that results in the humanin vivobiosynthesis of a family of compounds with potential antiviral activity. Using nuclear magnetic resonance (NMR) spectroscopy, we detected a characteristic spin-system motif indicative of the presence of an extended panel of urinary and serum metabolites during the acute viral phase. The structure of eight of nucleoside analogues was elucidated (six of which have not previously been reported in human urine), and subsequently confirmed by total-synthesis and matrix spiking. The molecular structures of the nucleoside analogues and their correlation with an array of serum cytokines, including IFN-α2, IFN-γ and IL-10, suggest an association with the viperin enzyme contributing to an endogenous innate immune defense mechanism against viral infection.

A series of 12β-methyl-18-nor-avicholic acid analogues was prepared and evaluated for activity at TGR5 and FXR. Compounds 46 and 53 emerged as low-micromolar TGR5 agonists, providing potential new templates for further development.

Diffuse gastric cancer and lobular breast cancer are aggressive malignancies that are frequently associated with inactivating mutations in the tumor suppressor gene

Parkinson’s Disease is the most common neurodegenerative movement disorder globally, with prevalence increasing. There is an urgent need for new therapeutics which are disease-modifying rather than symptomatic. Mitochondrial dysfunction is a well-documented mechanism in both sporadic and familial Parkinson’s Disease. Furthermore, ursodeoxycholic acid (UDCA) has been identified as a bile acid which leads to increased mitochondrial function in multiple in vitro and in vivo models of Parkinson’s Disease. Here, we describe the synthesis of novel C-nor-D-homo bile acid derivatives and the 12-hydroxy-methylated derivative of lagocholic acid (7) and their biological evaluation in fibroblasts from patients with either sporadic or LRRK2 mutant Parkinson’s Disease. These compounds boost mitochondrial function to a similar level or above that of UDCA in many assays; notable, however, is their ability to boost mitochondrial function to a higher level and at lower concentrations than UDCA specifically in the fibroblasts from LRRK2 patients. Our study indicates that novel bile acid chemistry could lead to the development of more efficacious bile acids which increase mitochondrial function and ultimately cellular health at lower concentrations proving attractive potential novel therapeutics for Parkinson’s Disease.

Millions of people are infected by the Dengue and Zika viruses each year, which can result in serious illness, permanent disability or death. There are currently no FDA-approved antivirals for treating infection by these viruses. Galidesivir is an adenosine nucleoside analog which can attenuate flavivirus replication in cell-based and animal models of infection. Galidesivir is converted to the triphosphorylated form by host kinases, and subsequently incorporated into viral RNA by viral RNA-dependent RNA polymerases, leading to the termination of RNA synthesis via an unknown mechanism. Here we report the directin vitrotesting of the effects of Galidesivir triphosphate on RNA synthesis by the polymerases of Dengue-2 and Zika virus. Galidesivir triphosphate was chemically synthesized and inhibition of RNA synthesis followed using a continuous fluorescence-based assay. Galidesivir triphosphate was equipotent against the polymerase activity of Dengue-2 and Zika, with IC50values of 42 ± 12 μM and 47 ± 5 μM, respectively. This modest potencyin vitrois consistent with results previously obtained in cell-based antiviral assays and suggests that the binding affinity for Galidesivir triphosphate is similar to the natural ATP substrate that it closely mimics. The inhibition assay we have developed will allow the rapid screening of Galidesivir and related compounds against other flavivirus polymerases, and the availability of Galidesivir triphosphate will allow detailed analysis of its mechanism of action.HighlightsGalidesivir triphosphate was chemically synthesized.A continuous assay detecting double-stranded RNA formation was optimized for polymerase inhibition studies.Galidesivir triphosphate has moderate potency against DENV2 and ZIKA polymerase activity.The availability of Galidesivir triphosphate will facilitate study of its mechanism of action.

The isocitrate lyase paralogs of

Helicobacter pylori is a Gram-negative bacterium that is responsible for gastric and duodenal ulcers. H. pylori uses the unusual mqn pathway with aminofutalosine (AFL) as an intermediate for menaquinone biosynthesis. Previous reports indicate that hydrolysis of AFL by 5′-methylthioadenosine nucleosidase (HpMTAN) is the direct path for producing downstream metabolites in the mqn pathway. However, genomic analysis indicates jhp0252 is a candidate for encoding AFL deaminase (AFLDA), an activity for deaminating aminofutolasine. The product, futalosine, is not a known substrate for bacterial MTANs. Recombinant jhp0252 was expressed and characterized as an AFL deaminase (HpAFLDA). Its catalytic specificity includes AFL, 5′-methylthioadenosine, 5′-deoxyadenosine, adenosine, and S-adenosylhomocysteine. The k(cat)/K(m) value for AFL is 6.8 × 10(4) M(−1) s(−1), 26-fold greater than that for adenosine. 5′-Methylthiocoformycin (MTCF) is a slow-onset inhibitor for HpAFLDA and demonstrated inhibitory effects on H. pylori growth. Supplementation with futalosine partially restored H. pylori growth under MTCF treatment, suggesting AFL deamination is significant for cell growth. The crystal structures of apo-HpAFLDA and with MTCF at the catalytic sites show a catalytic site Zn(2+) or Fe(2+) as the water-activating group. With bound MTCF, the metal ion is 2.0 Å from the sp(3) hydroxyl group of the transition state analogue. Metabolomics analysis revealed that HpAFLDA has intracellular activity and is inhibited by MTCF. The mqn pathway in H. pylori bifurcates at aminofutalosine with HpMTAN producing adenine and depurinated futalosine and HpAFLDA producing futalosine. Inhibition of cellular HpMTAN or HpAFLDA decreased the cellular content of menaquinone-6, supporting roles for both enzymes in the pathway.

Innate immune responses induce hundreds of interferon-stimulated genes (ISGs). Viperin, a member of the radical S-adenosyl methionine (SAM) superfamily of enzymes, is the product of one such ISG that restricts the replication of a broad spectrum of viruses. Here, we report a previously unknown antiviral mechanism in which viperin activates a ribosome collision-dependent pathway that inhibits both cellular and viral RNA translation. We found that the radical SAM activity of viperin is required for translation inhibition and that this is mediated by viperin's enzymatic product, 3'-deoxy-3',4'-didehydro-CTP (ddhCTP). Viperin triggers ribosome collisions and activates the MAPKKK ZAK pathway that in turn activates the GCN2 arm of the integrated stress response pathway to inhibit translation. The study illustrates the importance of translational repression in the antiviral response and identifies viperin as a translation regulator in innate immunity.