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An systematic phenotypic screen of the mouse gut microbiome for metabolites with an immunomodulatory effect identified Muribaculum intestinaleas one of only two members with an oversized effect on T-cell populations. Here we report the identification and characterization of a lipid, MiCL-1, as the responsible metabolite. MiCL-1 is an 18:1-16:0 cardiolipin, whose close relatives are found on concave lipid surfaces of both mammals and bacteria. MiCL-1 was synthesized to confirm the structural analysis and functionally characterized in cell-based assays. It has a highly restrictive structure–activity profile, as its chain-switched analog fails to induce responses in any of our assays. MiCL-1 robustly induces the production of pro-inflammatory cytokines like TNF-α, IL-6, and IL-23, but has no detectable effect on the anti-inflammatory cytokine IL-10. As is the case with other recently discovered immunomodulatory lipids, MiCL-1 requires functional TLR2 and TLR1 but not TLR6 in cell-based assays.

Coley’s toxins, an early and enigmatic form of cancer (immuno)therapy, were based on preparations of Streptococcus pyogenes. As part of a program to explore bacterial metabolites with immunomodulatory potential, S. pyogenesmetabolites were assayed in a cell-based immune assay, and a single membrane lipid, 18:1/18:0/18:1/18:0 cardiolipin, was identified. Its activity was profiled in additional cellular assays, which showed it to be an agonist of a TLR2–TLR1 signaling pathway with a 6 μM EC50and robust TNF-α induction. A synthetic analog with switched acyl chains had no measurable activity in immune assays. The identification of a single immunogenic cardiolipin with a restricted structure–activity profile has implications for immune regulation, cancer immunotherapy, and poststreptococcal autoimmune diseases.

The human immune system detects potentially pathogenic microbes with receptors that respond to microbial metabolites. While the overall immune signaling pathway is known in considerable detail, the initial molecular signals, the microbially produced immunogens, for important diseases like Lyme disease (LD) are often not well-defined. The immunogens for LD are produced by the spirochete Borrelia burgdorferi, and a galactoglycerolipid (1) has been identified as a key trigger for the inflammatory immune response that characterizes LD. This report corrects the original structural assignment of 1to 3, a change of an α-galactopyranose to an α-galactofuranose headgroup. The seemingly small change has important implications for the diagnosis, prevention, and treatment of LD.

Fourteen azaphilone-type polyketides (1–14), including nine new ones (1–6and 8–10), were isolated from cultures of Vitex rotundifolia-associated Penicilliumsp. JVF17, and their structures were determined by spectroscopic analysis together with computational methods and chemical reactions. Neuroprotective effects of the isolated compounds were evaluated against glutamate-induced neurotoxicity. Treatment with compounds 3, 6, 7, and 11–14increased cell viabilities of hippocampal neuronal cells damaged by glutamate, with compound 12being the most potent. Compound 12markedly decreased intracellular Ca2+and nuclear condensation levels. Mechanistically, molecular markers of apoptosis induced by treatment with glutamate, i.e., phosphorylation of MAPKs and elevated Bax/Bcl-2 expression ratio, were significantly lowered by compound 12. The azaphilones with an isoquinoline core structure were more active than those with pyranoquinones, but N-substitution decreased the activity. This study, including the structure–activity relationship, indicates that the azaphilone scaffold is a promising lead toward the development of novel neuroprotective agents.

Glutamate neurotoxicity has been implicated in neuronal death in both acute CNS injury and in chronic neurodegenerative diseases. Five unique cyclic depsipeptides with neuroprotective activity, colletotrichamides A–E (1–5), were isolated from cultures of a halophyte Suaeda japonica-associated fungus, Colletotrichum gloeosporioidesJS419. Spectroscopic analysis revealed that they were glycosylated cyclic lipodepsipeptides. Their relative configurations were determined by ROESY and J-based configuration analysis, and absolute configurations were established by chemical reactions including modified Mosher’s method, advanced Marfey’s method, and sugar derivatization. This is the first report of a glycosylated dimethyl-trioxygenated dodecanoyl moiety, and the relative as well as absolute stereochemistry was elucidated herein for the first time. Colletotrichamide C exhibited strong neuroprotective activity against glutamate in hippocampal HT22 cells.

Roots of Glehnia littoralishave been used to heal stroke as a traditional medicine. Even though many studies on this plant have been conducted, the secondary metabolites produced by its endophytes and their bioactivities have not been investigated thus far. Therefore, a new meroditerpenoid named sartorypyrone E (1) and eight known compounds (2–9) were isolated from extracts of cultured Neosartorya fischeriJS0553, an endophyte of G. littoralis. The isolated metabolites were identified using spectroscopic methods and chemical reaction, based on a comparison to literature data. Relative and absolute stereochemistries of compound 1were also elucidated. To identify the protective effects of isolated compounds (1–9) in HT22 cells against glutamate-induced cytotoxicity, we assessed inhibition of cell death, intracellular reactive oxygen species (ROS) accumulation, and calcium ion (Ca2+) influx. Among the isolates, compound 8, identified as fischerin, showed significant neuroprotective activity on glutamate-mediated HT22 cell death through inhibition of ROS, Ca2+influx, and phosphorylation of mitogen-activated protein kinase, including c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p38. The results suggested that the metabolites produced by the endophyte N. fischeriJS0553 might be related to the neuroprotective activity of its host plant, G. littoralis.

Colletotrichumsp. JS-0367 was isolated from Morus alba(mulberry), identified, and cultured on a large scale for chemical investigation. One new anthraquinone (1) and three known anthraquinones (2–4) were isolated and identified using spectroscopic methods including 1D/2D-NMR and HRESIMS. Although the neuroprotective effects of some anthraquinones have been reported, the biological activities of the four anthraquinones isolated in this study have not been reported. Therefore, the neuroprotective effects of these compounds were determined against murine hippocampal HT22 cell death induced by glutamate. Compound 4, evariquinone, showed strong protective effects against HT22 cell death induced by glutamate by the inhibition of intracellular ROS accumulation and Ca2+influx triggered by glutamate. Immunoblot analysis revealed that compound 4reduced the phosphorylation of MAPKs (JNK, ERK1/2, and p38) induced by glutamate. Furthermore, compound 4strongly attenuated glutamate-mediated apoptotic cell death.

Wilson’s disease (WD) is an autosomal recessive disorder caused by ATP7Bgene mutation. The frequency of WD is about 1 in 30 000 worldwide. In the present study, we screened 14 835 dried blood spots (DBSs) from asymptomatic Korean neonates and retrospectively reviewed massively parallel sequencing of 1090 control individuals to estimate carrier frequency. TaqMan real-time PCR assays were conducted to detect six mutations that account for 58.3% of mutations in Korean WD patients: c.2333G>T (p.Arg778Leu), c.2621C>T (p.Ala874Val), c.3086C>T (p.Thr1029Ile), c.3247C>T (p.Leu1083Phe), c.3556G>A (p.Gly1186Ser) and c.3809A>G (p.Asn1270Ser). We also retrospectively reviewed data from 1090 individuals with various indications other than WD for whom whole-exome or panel sequencing data were available. Mutant allele frequency based on the six most common mutations was 0.0067 among the total of 14 835 DBSs screened. Given that these six mutations account for 58.3% of mutations in Korean WD patients, the corrected mutant allele frequency is 0.0115 (95% confidence interval (CI): 0.0103–0.0128). Corresponding incidence (q2) and carrier frequency (2pq) were estimated to be 1:7561 and 1:44, respectively. In retrospective data analysis of 1090 control individuals, allele frequency of pathogenic or likely pathogenic variants was 0.0096 (95% CI: 0.0063–0.0146). Corresponding carrier frequency was estimated to be 1:53. Estimated allele and carrier frequencies based on DNA screening were relatively higher than those reported previously based on clinical ascertainment.

Three new cyclic peptide–polyketide hybrids (1–3) and two new chaetiacandin-type polyketides (4and 5) along with nine known compounds were isolated from cultures of a halophyte-associated fungus, Colletotrichum gloeosporioidesJS0417. Spectroscopic analysis revealed that 1–3were cyclic depsipeptides where 3,5,11-trihydroxy-2,6-dimethyldodecanoic acid was linked to two amino acids through amide and ester bonds to form a 12-membered ring. Relative and absolute configurations for the peptides were determined with spectroscopic analysis and chemical reactions. The cyclic depsipeptides 2and 6were determined to act as strong adiponectin-secretion-promoting modulators with potential to treat metabolic diseases associated with hypoadiponectinemia. Notably, a known compound, tryptophol, significantly inhibited PGE2synthesis and also promoted adiponectin secretion, exhibiting a similar biological activity profile to aspirin, but with greater potency. The presence of an isoleucine moiety and non-glycosylation may be important for biological activity of the cyclic peptide–polyketide hybrids, and non-methoxylation of the side chain may influence activity of the indole derivatives.