Pu-erh tea increases the metabolite Cinnabarinic acid to improve circadian rhythm disorder-induced obesity

Obesity is one of the circadian rhythm disorders (CRD)-mediated metabolic disorder syndromes. Pu-erh tea is a viable dietary intervention for CRD, however its effect on CRD-induced obesity is unclear. Here, we found that Pu-erh tea improved obesity in CRD-induced mice, which stemmed from the production of Cinnabarinic acid (CA). CA promoted adipose tissue lipolysis and thermogenic response (HSL, ATGL, Pparα, CKB, UCP1) and increased adipocyte sensitivity to hormones and neurotransmitters by targeting the expression of adipose tissue receptor proteins (Q6KAT8, P51655, A2AKQ0, M0QWX7, Q6ZQ33, and mGluR4). This improved mitochondrial activity and facilitated adipose tissue metabolic processes, thereby accelerating glucolipid metabolism. Also, CA-induced alterations in gut microbes and short-chain fatty acids further improved CRD-mediated lipid accumulation. These results suggest that the increase of CA caused by Pu-erh tea, targeted to adipose tissue via the metabolite-blood circulation-adipose tissue axis, maybe a key mechanism for reducing the development of CRD-induced obesity.

Cinnabarinic acid from Trametes coccinea fruiting bodies exhibits antibacterial activity through inhibiting the biofilm formation

Wild mushrooms are rich sources of natural compounds with potent bioactive properties. Several important metabolites have been reported from mushrooms, which possess clinically important bioactive properties like antibacterial, anticancer, antidiabetic, and neuroprotective activity. In this study, we have evaluated the antimicrobial activity of Trametes coccinea fruiting body extracts against different bacterial isolates, viz., Bacillus subtilis, Bacillus cereus, and Escherichia coli. Fruiting bodies of three T. coccinea samples, of which two were collected from Santipur, Arunachal Pradesh and one collected from Jorhat, Assam, were used for extraction using methanol. The extracts showed significant antimicrobial activity against all the test bacteria. Minimum Inhibitory Concentration (MIC) of the extracts against Bacillus subtilis, Bacillus cereus, and Escherichia coli was recorded as 400 µg/ml, 400 µg/ml, and 300 µg/ml, respectively. Furthermore, the bioactive compounds of the extract were separated and detected using Thin Layer Chromatography (TLC). Presence of cinnabarinic acid (CBA)-a potent antimicrobial compound- was detected in TLC, which was further confirmed through High Performance Liquid Chromatography (HPLC) and Electrospray Ionization-Mass Spectrometry (ESI-MS). Cinnabarinic acid was able to inhibit the formation of biofilms in Bacillus subtilis and B. cereus, suggesting that the compound can be beneficial in the management of biofilm-based antimicrobial resistance.

Genome sequence of the fungus Pycnoporus sanguineus, which produces cinnabarinic acid and pH- and thermo- stable laccases

Pycnoporus sanguineus, an edible mushroom, produces antimicrobial and antitumor bioactive compounds and pH- and thermo- stable laccases that have multiple potential biotechnological applications. Here we reported the complete genome of the species Pycnoporus sanguineus ACCC 51,180 by using the combination of Illumina HiSeq X Ten and the PacBio sequencing technology. The represented genome is 36.6 Mb composed of 59 scaffolds with 12,086 functionally annotated protein-coding genes. The genome of Pycnoporus sanguineus encodes at least 19 biosynthetic gene clusters for secondary metabolites, including a terpene cluster for biosynthesis of the antitumor clavaric acid. Seven laccases were identified, while 22 genes were found to be involved in the kynurenine pathway in which the intermediate metabolite 3-hydroxyanthranilic acid were catalyzed by laccases into cinnabarinic acid. This study represented the third genome of the genus Pycnoporus, and wound facilitate the exploration of useful sources from Pycnoporus sanguineus for future industrial applications.

Toxicity and cardiac effects of acute exposure to tryptophan metabolites on the kynurenine pathway in early developing zebrafish (Danio rerio) embryos

Defects in tryptophan metabolism on the l-kynurenine pathway (KP) are implicated in a number of human diseases, including chronic kidney disease, brain edema or injury, tuberculosis and malaria - as well as cancer, neurodegenerative and autoimmune disorders. However, it is unclear to what extent detrimental effects of exposure to tryptophan metabolites might impact the early development of organism. Thus, this study examined the effects of KP exposure in zebrafish embryos starting at the blastula period (4hpf) and the segmentation stage (24hpf). 24-hour EC₅₀ and LC₅₀ values were determined in 4hpf embryos as: 26.74 and 331.6μM for anthranilic acid (AA), 62.88 and 616.4μM for quinolinic acid (QUIN), and EC₅₀ - 96.10μM for picolinic acid (PA) and LC₅₀ - 400μM in kynurenic acid (KYNA). In addition, treatment with nanomolar concentrations of KYNA (50nM, 48 and 72hpf embryos) caused a dose-dependent increase in heartbeat. The increase was also seen with l-kyn treatment (50μM, 72hpf), which was the opposite of other applied l-kyn metabolites. A significant drop in heartbeat was observed after a 20-min acute exposure to 626μM PA, 594μM XA and 499μM QUIN, and complete recovery was seen only when PA had been removed. Concentrations of KP metabolites reached in people with different pathological conditions did not exert toxicity to zebrafish embryos and seems to be safe for developing embryos and therefore, the risk of developing impairments in pregnancy of women carrying KP-associated pathologies is initially low.

Cinnabarinic acid, an endogenous agonist of type-4 metabotropic glutamate receptor, suppresses experimental autoimmune encephalomyelitis in mice

Cinnabarinic acid (CA) is an endogenous metabolite of the kynurenine pathway which acts as an orthosteric agonist of type-4 metabotropic glutamate receptor (mGlu4). We now report that systemic administration of CA (0.1-10 mg/kg, i.p.) was highly protective against experimental autoimmune encephalomyelitis (EAE) induced by the myelin oligodendrocyte glycoprotein (MOG35-55) peptide, which models multiple sclerosis in mice. Full protection against EAE required daily injections of CA since the time of immunization, similarly to what reported for the mGlu4 enhancer N-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1acarboxamide (PHCCC). CA treatment boosted an immune response dominated by regulatory T (Treg) cells at the expenses of Th17 cells. In addition, exogenous CA enhanced endogenous CA formation in lymphocytes, suggesting the occurrence of a positive feedback loop sustaining immune tolerance. To examine whether activation of mGlu4 could account for the protective activity of CA against EAE, we used mGlu4 knockout mice. As expected, these mice displayed a more severe form of EAE in response to immunization. CA was still protective against EAE in mGlu4-deficient mice, although its action was significantly reduced both at high and low CA doses. This suggests that the action of CA against neuroinflammation involves multiple mechanisms including the activation of mGlu4. These data further suggest that CA is one possible bridge between activation of the kynurenine pathway and immune tolerance aimed at restraining neuroinflammation.

Zonisamide regulates basal ganglia transmission via astroglial kynurenine pathway

To clarify the anti-parkinsonian mechanisms of action of zonisamide (ZNS), we determined the effects of ZNS on tripartite synaptic transmission associated with kynurenine (KYN) pathway (KP) in cultured astrocytes, and transmission in both direct and indirect pathways of basal ganglia using microdialysis. Interactions between cytokines [interferon-γ (IFNγ) and tumor-necrosis factor-α (TNFα)] and ZNS on astroglial releases of KP metabolites, KYN, kynurenic-acid (KYNA), xanthurenic-acid (XTRA), cinnabarinic-acid (CNBA) and quinolinic-acid (QUNA), were determined by extreme liquid-chromatography with mass-spectrometry. Interaction among metabotropic glutamate-receptor (mGluR), KP metabolites and ZNS on striato-nigral, striato-pallidal GABAergic and subthalamo-nigral glutamatergic transmission was examined by microdialysis with extreme liquid-chromatography fluorescence resonance-energy transfer detection. Acute and chronic ZNS administration increased astroglial release of KYN, KYNA, XTRA and CNBA, but not QUNA. Chronic IFNγ administration increased the release of KYN, KYNA, CNBA and QUNA, but had minimal inhibitory effect on XTRA release. Chronic TNFα administration increased CNBA and QUNA, but not KYN, KYNA or XTRA. ZNS inhibited IFNγ-induced elevation of KYN, KYNA and QUNA, but enhanced IFNγ-induced that of CNBA. TNFα-induced rises in CNBA and QUNA were inhibited by ZNS. ZNS inhibited striato-nigral GABAergic, striato-pallidal GABAergic and subthalamo-nigral glutamatergic transmission via activation of groups II and III mGluRs. ZNS enhanced astroglial release of endogenous agonists of group II mGluR, XTRA and group III mGluR, CNBA. Activated endogenous mGluR agonists inhibited transmission in direct and indirect pathways of basal ganglia. These mechanisms contribute to effectiveness and well tolerability of ZNS as an adjunct treatment for Parkinson's disease during l-DOPA monotherapy. This article is part of the Special Issue entitled 'The Synaptic Basis of Neurodegenerative Disorders'.